Methods and devices for reading microarrays

ABSTRACT

In one embodiment of the invention, a method to image a probe array is described that includes focusing on a plurality of fiducials on a surface of an array. The method utilizes obtaining the best z position of the fiducials and using a surface fitting algorithm to produce a surface fit profile. One or more surface non-flatness parameters can be adjusted to improve the flatness image of the array surface to be imaged.

RELATED APPLICATIONS

This application is a division of U.S. application Ser. No. 12/780,825,filed May 14, 2010, which claims priority to U.S. ProvisionalApplication No. 61/180,789, filed May 22, 2009. The entire contents ofthese applications are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

Systems and methods for examining biological material are provided. Inparticular, provided is the acquisition of images by exposing biologicalprobe arrays comprising probe features to an excitation light anddetecting the responsive emitted light from fluorescent labelsassociated with target molecule hybridized to the probes of one or moreprobe features.

Synthesized nucleic acid probe arrays, such as Affymetrix GENECHIP®probe arrays, and spotted probe arrays, have been used to generateunprecedented amounts of information about biological systems. Forexample, the GENECHIP® Human Genome U133 Plus 2.0 Array for expressionapplications available from Affymetrix, Inc. of Santa Clara, Calif., iscomprised of one microarray containing 1,300,000 oligonucleotidefeatures covering more than 47,000 transcripts and variants that include38,500 well characterized human genes. Similarly, the GENECHIP® Mapping500K Array Set for genotyping applications available from Affymetrix,Inc. of Santa Clara, Calif., is comprised of two arrays, each capable ofgenotyping on average 250,000 SNPs. Analysis of expression or genotypingdata from such microarrays may lead to the development of new drugs andnew diagnostic tools.

SUMMARY OF THE INVENTION

A method to image a probe array is provided according to an embodimentof the invention. The method includes focusing on a plurality offiducials on a surface of an array. A plurality of images is taken at aplurality of various z positions. The sharpness at each z position isdetermined by employing various software program embodiments. A best zposition is chosen by comparing the images of the various z positionsand choosing the sharpest image. The above steps are repeated until thebest z position of each fiducial on the probe array is determined. Themeasurement data are transmitted to a computer, wherein the computerincludes a software program having one or more surface fittingalgorithms. A surface fit profile is calculated on the computeremploying the surface fitting algorithm(s) and using the transmittedmeasurement data. Based on the calculations of the surface fit profile,one or more surface non-flatness parameters can be adjusted to improvethe image flatness of the surface image of the probe array. The stepsabove can be repeated to obtain an image of the probe array.

In alternate embodiments, the imaging method may include a number offiducials, for example, at least 4, at least 5 and at least 9 fiducials.The surface fitting algorithm may include, but does not necessarily haveto include, a least square, sub-plane surface fit, and B spline surfacefit.

In another embodiment, the imaging method includes the array on a tiltstage which is discussed later in the application. Focusing the arrayincludes tilting the tilt stage so that the array surface is madeparallel to a focal plane of a microscope objective.

In a further embodiment, the surface non-flatness parameters may includeone or more of an array tilt, stage movement effect and opticalparameters. In a further embodiment, a focal plane may be adjusted bymoving a lens.

In an additional embodiment, the provided is a method of manufacturing afilter slider for reading a biological array. A linear slide and aplurality of filter sets are provided in this embodiment. The filtersets are mounted in a fixture that is mounted on a linear slide. Alinear actuator is also provided and coupled to the linear slide suchthat the filer slider functions properly even if the linear actuator ismisaligned relative to the linear slide. The linear actuator comprises amotor. In an alternate embodiment, the motor is a stepping motor and ablade slider, such as a steel shim stock coupled to the linear actuatorwith the filter slider.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a functional block diagram of one embodiment of ascanner system enabled to scan a probe array and computer system forimage acquisition and analysis.

FIG. 2 illustrates a functional block diagram of one embodiment of thescanner-computer system of FIG. 1, including scanner optics anddetectors.

FIG. 3 illustrates a simplified graphical representation of the scanneroptics and detectors of FIG. 2, suitable for providing excitation lightand the detection of emission signals.

FIGS. 4A and 4B illustrate images of a sub-array. FIG. 4A illustrates afluorescence image of a sub-array. FIG. 4B illustrates an image of asub-array showing the spatial relationship between chrome features andfluorescent features; and

FIGS. 5A, 5B, and 5C illustrate a 4-point auto-focusing method accordingto an embodiment of the present invention. FIG. 5A shows the location ofthe 4 points on a wafer. FIG. 5B shows a scanned image of the resultsfrom the 4 points array surface analysis and FIG. 5C shows thecomparison of the array surface characterization between the“calculated” surface and the actual surface.

FIGS. 6A, 6B, and 6C illustrate a 5-point auto-focusing method accordingto another embodiment of the present invention. FIG. 6A shows thelocation of the 5 points on an array. FIG. 6B shows a scanned image ofthe results from the 5 points array surface and FIG. 6C shows thecomparison of the array surface characterization between the“calculated” surface and the actual surface.

FIGS. 7A, 7B, 7C, 7D and 7E illustrate a 9-point auto-focusing methodaccording to a further embodiment of the present invention. FIG. 7Ashows the location of the 9 points on an array. FIG. 7B shows a scannedimage of the results from the 9 points array surface. FIGS. 7C, 7D, and7E show the comparisons of the array surface characterization betweenthe “calculated” surface using various fitting algorithms and the actualsurface.

FIG. 8 illustrates a filter slider assembly according to an embodimentof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to exemplary embodiments of theinvention. While the invention will be described in conjunction with theexemplary embodiments, it will be understood that they are not intendedto limit the invention to these embodiments. On the contrary, theinvention is intended to encompass alternatives, modifications andequivalents, which may be included within the spirit and scope of theinvention.

The invention relates to diverse fields impacted by the nature ofmolecular interaction, including chemistry, biology, medicine anddiagnostics. Methods disclosed herein are advantageous in fields, suchas those in which genetic information is required quickly, as inclinical diagnostic laboratories or in large-scale undertakings such asthe Human Genome Project.

The present invention has many embodiments and relies on many patents,applications and other references for details known to those of the art.Therefore, when a patent, application, or other reference is cited orrepeated below, it should be understood that the entire disclosure ofthe document cited is incorporated by reference in its entirety for allpurposes as well as for the proposition that is recited. All documents,i.e., publications and patent applications, cited in this disclosure,including the foregoing, are incorporated herein by reference in theirentireties for all purposes to the same extent as if each of theindividual documents were specifically and individually indicated to beso incorporated herein by reference in its entirety.

As used in this application, the singular form “a,” “an,” and “the”include plural references unless the context clearly dictates otherwise.For example, the term “an agent” includes a plurality of agents,including mixtures thereof.

An individual is not limited to a human being but may also be otherorganisms including, but not limited to, mammals, plants, bacteria, orcells derived from any of the above.

Throughout this disclosure, various aspects of this invention can bepresented in a range format. It should be understood that when adescription is provided in range format, this is merely for convenienceand brevity and should not be construed as an inflexible limitation onthe scope of the invention. Accordingly, the description of a rangeshould be considered to have specifically disclosed all the possiblesub-ranges as well as individual numerical values within that range. Forexample, description of a range such as from 1 to 6 should be consideredto have specifically disclosed sub-ranges such as from 1 to 3, from 1 to4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well asindividual numbers within that range, for example, 1, 2, 3, 4, 5, and 6.This applies regardless of the breadth of the range.

The practice of the present invention may employ, unless otherwiseindicated, conventional techniques and descriptions of organicchemistry, polymer technology, molecular biology (including recombinanttechniques), cell biology, biochemistry, and immunology, which arewithin the skill of one of skill in the art. Such conventionaltechniques include polymer array synthesis, hybridization, ligation, anddetection of hybridization using a detectable label. Specificillustrations of suitable techniques are provided by reference to theexamples hereinbelow. However, other equivalent conventional proceduresmay also be employed. Such conventional techniques and descriptions maybe found in standard laboratory manuals, such as Genome Analysis: ALaboratory Manual Series (Vols. I-IV), Using Antibodies: A LaboratoryManual, Cells: A Laboratory Manual, PCR Primer: A Laboratory Manual, andMolecular Cloning: A Laboratory Manual (all from Cold Spring HarborLaboratory Press), Stryer, L. (1995), Biochemistry, 4th Ed., Freeman,New York, Gait, Oligonucleotide Synthesis: A Practical Approach, (1984),IRL Press, London, Nelson and Cox (2000), Lehninger, Principles ofBiochemistry, 3^(rd) Ed., W.H. Freeman Pub., New York, N.Y., and Berg etal. (2002), Biochemistry, 5^(th) Ed., W.H. Freeman Pub., New York, N.Y.,all of which are herein incorporated in their entirety by reference forall purposes.

The present invention may employ solid substrates, including arrays insome embodiments. Methods and techniques applicable to polymer(including protein) array synthesis have been described in U.S. patentapplication Ser. No. 09/536,841 (abandoned), WO Application Serial No.00/58516, U.S. Pat. Nos. 5,143,854, 5,242,974, 5,252,743, 5,324,633,5,384,261, 5,405,783, 5,424,186, 5,451,683, 5,482,867, 5,491,074,5,527,681, 5,550,215, 5,571,639, 5,578,832, 5,593,839, 5,599,695,5,624,711, 5,631,734, 5,795,716, 5,831,070, 5,837,832, 5,856,101,5,858,659, 5,936,324, 5,968,740, 5,974,164, 5,981,185, 5,981,956,6,025,601, 6,033,860, 6,040,193, 6,090,555, 6,136,269, 6,269,846 and6,428,752, and in PCT Application Serial Nos. PCT/US99/00730(International Publication No. WO 99/36760) and PCT/US01/04285(International Publication No. WO 01/58593), which are all incorporatedherein by reference in their entirety for all purposes.

Patents that describe synthesis techniques in specific embodimentsinclude U.S. Pat. Nos. 5,412,087, 6,147,205, 6,262,216, 6,310,189,5,889,165, and 5,959,098. Nucleic acid arrays are described in many ofthe above patents, but the same techniques are applied to polypeptidearrays.

Nucleic acid arrays that are useful in the present invention include,but are not limited to, those that are commercially available fromAffymetrix (Santa Clara, Calif.) under the brand name GENECHIP®. Examplearrays are shown on the website at Affymetrix.com.

The present invention contemplates many uses for polymers attached tosolid substrates. These uses include, but are not limited to, geneexpression monitoring, profiling, library screening, genotyping anddiagnostics. Methods of gene expression monitoring and profiling aredescribed in U.S. Pat. Nos. 5,800,992, 6,013,449, 6,020,135, 6,033,860,6,040,138, 6,177,248 and 6,309,822. Genotyping methods, and usesthereof, are disclosed in U.S. patent application Ser. No. 10/442,021(abandoned) and U.S. Pat. Nos. 5,856,092, 6,300,063, 5,858,659,6,284,460, 6,361,947, 6,368,799, 6,333,179, and 6,872,529. Other usesare described in U.S. Pat. Nos. 5,871,928, 5,902,723, 6,045,996,5,541,061, and 6,197,506.

The present invention also contemplates sample preparation methods incertain embodiments. Prior to, or concurrent with, genotyping, thegenomic sample may be amplified by a variety of mechanisms, some ofwhich may employ PCR. (See, for example, PCR Technology: Principles andApplications for DNA Amplification, Ed. H. A. Erlich, Freeman Press, NY,N.Y., 1992; PCR Protocols: A Guide to Methods and Applications, Eds.Innis, et al., Academic Press, San Diego, Calif., 1990; Mattila et al.,Nucleic Acids Res., 19:4967, 1991; Eckert et al., PCR Methods andApplications, 1:17, 1991; PCR, Eds. McPherson et al., IRL Press, Oxford,1991; and U.S. Pat. Nos. 4,683,202, 4,683,195, 4,800,159 4,965,188, and5,333,675, each of which is incorporated herein by reference in theirentireties for all purposes. The sample may also be amplified on thearray. (See, for example, U.S. Pat. No. 6,300,070 and U.S. patentapplication Ser. No. 09/513,300 (abandoned), all of which areincorporated herein by reference).

Other suitable amplification methods include the ligase chain reaction(LCR) (see, for example, Wu and Wallace, Genomics, 4:560 (1989),Landegren et al., Science, 241:1077 (1988) and Barringer et al., Gene,89:117 (1990)), transcription amplification (Kwoh et al., Proc. Natl.Acad. Sci. USA, 86:1173 (1989) and WO 88/10315), self-sustained sequencereplication (Guatelli et al., Proc. Nat. Acad. Sci. USA, 87:1874 (1990)and WO 90/06995), selective amplification of target polynucleotidesequences (U.S. Pat. No. 6,410,276), consensus sequence primedpolymerase chain reaction (CP-PCR) (U.S. Pat. No. 4,437,975),arbitrarily primed polymerase chain reaction (AP-PCR) (U.S. Pat. Nos.5,413,909 and 5,861,245) and nucleic acid based sequence amplification(NABSA). (See also, U.S. Pat. Nos. 5,409,818, 5,554,517, and 6,063,603,each of which is incorporated herein by reference). Other amplificationmethods that may be used are described in, for instance, U.S. Pat. Nos.6,582,938, 5,242,794, 5,494,810, and 4,988,617, each of which isincorporated herein by reference.

Additional methods of sample preparation and techniques for reducing thecomplexity of a nucleic sample are described in Dong et al., GenomeResearch, 11:1418 (2001), U.S. Pat. Nos. 6,361,947, 6,391,592,6,632,611, 6,872,529 and 6,958,225, and in U.S. patent application Ser.No. 09/916,135 (abandoned).

Methods for conducting polynucleotide hybridization assays have beenwell developed in the art. Hybridization assay procedures and conditionswill vary depending on the application and are selected in accordancewith known general binding methods, including those referred to inManiatis et al., Molecular Cloning: A Laboratory Manual, 2^(nd) Ed.,Cold Spring Harbor, N.Y, (1989); Berger and Kimmel, Methods inEnzymology, Guide to Molecular Cloning Techniques, Vol. 152, AcademicPress, Inc., San Diego, Calif. (1987); Young and Davism, Proc. Nat'l.Acad. Sci., 80:1194 (1983). Methods and apparatus for performingrepeated and controlled hybridization reactions have been described in,for example, U.S. Pat. Nos. 5,871,928, 5,874,219, 6,045,996, 6,386,749,and 6,391,623 each of which are incorporated herein by reference.

The present invention also contemplates signal detection ofhybridization between ligands in certain embodiments. (See, U.S. Pat.Nos. 5,143,854, 5,578,832, 5,631,734, 5,834,758, 5,936,324, 5,981,956,6,025,601, 6,141,096, 6,185,030, 6,201,639, 6,218,803, and 6,225,625,U.S. patent application Ser. No. 10/389,194 (U.S. Patent ApplicationPublication No. 2004/0012676) and PCT Application PCT/US99/06097(published as WO 99/47964), each of which is hereby incorporated byreference in its entirety for all purposes).

The practice of the present invention may also employ conventionalbiology methods, software and systems. Computer software products of theinvention typically include, for instance, computer readable mediumhaving computer-executable instructions for performing the logic stepsof the method of the invention. Suitable computer readable mediuminclude, but are not limited to, a floppy disk, CD-ROM/DVD/DVD-ROM,hard-disk drive, flash memory, ROM/RAM, magnetic tapes, etc. Thecomputer executable instructions may be written in a suitable computerlanguage or combination of several computer languages. Basiccomputational biology methods which may be employed in the presentinvention are described in, for example, Setubal and Meidanis et al.,Introduction to Computational Biology Methods, PWS Publishing Company,Boston, (1997); Salzberg, Searles, Kasif, (Ed.), Computational Methodsin Molecular Biology, Elsevier, Amsterdam, (1998); Rashidi and Buehler,Bioinformatics Basics: Application in Biological Science and Medicine,CRC Press, London, (2000); and Ouelette and Bzevanis Bioinformatics: APractical Guide for Analysis of Gene and Proteins, Wiley & Sons, Inc.,2^(nd) ed., (2001). (See also, U.S. Pat. No. 6,420,108).

The present invention may also make use of various computer programproducts and software for a variety of purposes, such as probe design,management of data, analysis, and instrument operation. (See, U.S. Pat.Nos. 5,593,839, 5,795,716, 5,733,729, 5,974,164, 6,066,454, 6,090,555,6,185,561, 6,188,783, 6,223,127, 6,229,911 and 6,308,170).

Additionally, the present invention encompasses embodiments that mayinclude methods for providing genetic information over networks such asthe internet, as disclosed in, for instance, U.S. patent applicationSer. No. 10/197,621 (U.S. Patent Application Publication No.20030097222), Ser. No. 10/063,559 (U.S. Patent Application PublicationNo. 20020183936, abandoned), Ser. No. 10/065,856 (U.S. PatentApplication Publication No. 20030100995, abandoned), Ser. No. 10/065,868(U.S. Patent Application Publication No. 20030120432, abandoned), Ser.No. 10/328,818 (U.S. Patent Application Publication No. 20040002818,abandoned), Ser. No. 10/328,872 (U.S. Patent Application Publication No.20040126840, abandoned), Ser. No. 10/423,403 (U.S. Patent ApplicationPublication No. 20040049354, abandoned), and 60/482,389 (expired).

A. Definitions

The term “array” as used herein refers to an intentionally createdcollection of molecules which can be prepared either synthetically orbiosynthetically. The molecules in the array can be identical ordifferent from each other. The array can assume a variety of formats,including, but not limited to, libraries of soluble molecules, andlibraries of compounds tethered to resin beads, silica chips, or othersolid supports. An array may include polymers of a give length havingall possible monomer sequences made up of a specific bases set ofmonomers, or a specific subset of such an array. In other cases as arraymay be formed from inorganic materials (See Schultz et al PCTapplication WO 96/11878.).

The term “combinatorial synthesis strategy” as used herein refers to acombinatorial synthesis strategy is an ordered strategy for parallelsynthesis of diverse polymer sequences by sequential addition ofreagents which may be represented by a reactant matrix and a switchmatrix, the product of which is a product matrix. A reactant matrix is a1 column by m row matrix of the building blocks to be added. The switchmatrix is all or a subset of the binary numbers which can be ordered,between 1 and m arranged in columns. A “binary strategy” is one in whichat least two successive steps illuminate a portion, often half, of aregion of interest on the substrate. In a binary synthesis strategy, allpossible compounds which can be formed from an ordered set of reactantsare formed. In most embodiments, binary synthesis refers to a synthesisstrategy which also factors a previous addition step. For example, astrategy in which a switch matrix for a masking strategy halves regionsthat were previously illuminated, illuminating about half of thepreviously illuminated region and protecting the remaining half (whilealso protecting about half of previously protected regions andilluminating about half of previously protected regions). It will berecognized that binary rounds may be interspersed with non-binary roundsand that only a portion of a substrate may be subjected to a binaryscheme. A combinatorial “masking” strategy is a synthesis which useslight or other spatially selective deprotecting or activating agents toremove protecting groups from materials for addition of other materialssuch as amino acids.

The term “edge” as used herein refers to a boundary between two featureson a surface of a substrate. The sharpness of this edge, in terms ofreduced bleed over from one feature to another, is termed the “contrast”between the two features.

The term “feature” as used herein refers to a a selected region on asurface of a substrate in which a given polymer sequence is contained.Thus, where an array contains, e.g., 100,000 different positionallydistinct polymer sequences on a single substrate, there will be 100,000features.

The term “Functional group” as used herein refers to a reactive chemicalmoiety present on a given monomer, polymer or substrate surface.Examples of functional groups include, e.g., the 3′ and 5′ hydroxylgroups of nucleotides and nucleosides, as well as the reactive groups onthe nucleobases of the nucleic acid monomers, e.g., the exocyclic aminegroup of guanosine, as well as amino and carboxyl groups on amino acidmonomers.

The term “genome” as used herein is all the genetic material in thechromosomes of an organism. DNA derived from the genetic material in thechromosomes of a particular organism is genomic DNA. A genomic libraryis a collection of clones made from a set of randomly generatedoverlapping DNA fragments representing the entire genome of an organism.

The term “genotype” as used herein refers to the genetic information anindividual carries at one or more positions in the genome. A genotypemay refer to the information present at a single polymorphism, forexample, a single SNP. For example, if a SNP is biallelic and can beeither an A or a C then if an individual is homozygous for A at thatposition the genotype of the SNP is homozygous A or AA. Genotype mayalso refer to the information present at a plurality of polymorphicpositions.

The term “Hardy-Weinberg equilibrium” (HWE) as used herein refers to theprinciple that an allele that when homozygous leads to a disorder thatprevents the individual from reproducing does not disappear from thepopulation but remains present in a population in the undetectableheterozygous state at a constant allele frequency.

The term “hybridization” as used herein refers to the process in whichtwo single-stranded polynucleotides bind non-covalently to form a stabledouble-stranded polynucleotide; triple-stranded hybridization is alsotheoretically possible. The resulting (usually) double-strandedpolynucleotide is a “hybrid.” The proportion of the population ofpolynucleotides that forms stable hybrids is referred to herein as the“degree of hybridization.” Hybridizations are usually performed understringent conditions, for example, at a salt concentration of no morethan about 1 M and a temperature of at least 25° C. For example,conditions of 5×SSPE (750 mM NaCl, 50 mM NaPhosphate, 5 mM EDTA, pH 7.4)and a temperature of 25-30° C. are suitable for allele-specific probehybridizations or conditions of 100 mM MES, 1 M [Na+], 20 mM EDTA, 0.01%Tween-20 and a temperature of 30-50° C., or at about 45-50° C.Hybridizations may be performed in the presence of agents such asherring sperm DNA at about 0.1 mg/ml, acetylated BSA at about 0.5 mg/ml.As other factors may affect the stringency of hybridization, includingbase composition and length of the complementary strands, presence oforganic solvents and extent of base mismatching, the combination ofparameters is more important than the absolute measure of any one alone.Hybridization conditions suitable for microarrays are described in theGene Expression Technical Manual, 2004 and the GENECHIP® Mapping AssayManual, 2004.

The term “hybridization probes” as used herein are oligonucleotidescapable of binding in a base-specific manner to a complementary strandof nucleic acid. Such probes include peptide nucleic acids, as describedin Nielsen et al., Science 254, 1497-1500 (1991), LNAs, as described inKoshkin et al. Tetrahedron 54:3607-3630, 1998, and U.S. Pat. No.6,268,490, aptamers, and other nucleic acid analogs and nucleic acidmimetics.

The term “hybridizing specifically to” as used herein refers to thebinding, duplexing, or hybridizing of a molecule only to a particularnucleotide sequence or sequences under stringent conditions when thatsequence is present in a complex mixture (for example, total cellular)DNA or RNA.

The term “initiation biomonomer” or “initiator biomonomer” as usedherein is meant to indicate the first biomonomer which is covalentlyattached via reactive nucleophiles to the surface of the polymer, or thefirst biomonomer which is attached to a linker or spacer arm attached tothe polymer, the linker or spacer arm being attached to the polymer viareactive nucleophiles.

The term “isolated nucleic acid” as used herein mean an object speciesinvention that is the predominant species present (i.e., on a molarbasis it is more abundant than any other individual species in thecomposition). In one aspect, an isolated nucleic acid comprises at leastabout 50, 80 or 90% (on a molar basis) of all macromolecular speciespresent. In a further embodiment, the object species is purified toessential homogeneity (contaminant species cannot be detected in thecomposition by conventional detection methods).

The term “ligand” as used herein refers to a molecule that is recognizedby a particular receptor. The agent bound by or reacting with a receptoris called a “ligand,” a term which is definitionally meaningful only interms of its counterpart receptor. The term “ligand” does not imply anyparticular molecular size or other structural or compositional featureother than that the substance in question is capable of binding orotherwise interacting with the receptor. Also, a ligand may serve eitheras the natural ligand to which the receptor binds, or as a functionalanalogue that may act as an agonist or antagonist. Examples of ligandsthat can be investigated by this invention include, but are notrestricted to, agonists and antagonists for cell membrane receptors,toxins and venoms, viral epitopes, hormones (for example, opiates,steroids, etc.), hormone receptors, peptides, enzymes, enzymesubstrates, substrate analogs, transition state analogs, cofactors,drugs, proteins, and antibodies.

The term “linkage analysis” as used herein refers to a method of geneticanalysis in which data are collected from affected families, and regionsof the genome are identified that co-segregated with the disease in manyindependent families or over many generations of an extended pedigree. Adisease locus may be identified because it lies in a region of thegenome that is shared by all affected members of a pedigree.

The term “linkage disequilibrium” or sometimes referred to as “allelicassociation” as used herein refers to the preferential association of aparticular allele or genetic marker with a specific allele, or geneticmarker at a nearby chromosomal location more frequently than expected bychance for any particular allele frequency in the population. Forexample, if locus X has alleles A and B, which occur equally frequently,and linked locus Y has alleles C and D, which occur equally frequently,one would expect the combination AC to occur with a frequency of 0.25.If AC occurs more frequently, then alleles A and C are in linkagedisequilibrium. Linkage disequilibrium may result from natural selectionof certain combination of alleles or because an allele has beenintroduced into a population too recently to have reached equilibriumwith linked alleles. The genetic interval around a disease locus may benarrowed by detecting disequilibrium between nearby markers and thedisease locus. For additional information on linkage disequilibrium seeArdlie et al., Nat. Rev. Gen. 3:299-309, 2002.

The term “lod score” or “LOD” is the log of the odds ratio of theprobability of the data occurring under the specific hypothesis relativeto the null hypothesis. LOD=log [probability assuminglinkage/probability assuming no linkage].

The term “mixed population” or sometimes refer by “complex population”as used herein refers to any sample containing both desired andundesired nucleic acids. As a non-limiting example, a complex populationof nucleic acids may be total genomic DNA, total genomic RNA or acombination thereof. Moreover, a complex population of nucleic acids mayhave been enriched for a given population but include other undesirablepopulations. For example, a complex population of nucleic acids may be asample which has been enriched for desired messenger RNA (mRNA)sequences but still includes some undesired ribosomal RNA sequences(rRNA).

The term “monomer/building block” as used herein refers to a member ofthe set of smaller molecules which can be joined together to form alarger molecule or polymer. The set of monomers includes but is notrestricted to, for example, the set of common L-amino acids, the set ofD-amino acids, the set of natural or synthetic amino acids, the set ofnucleotides (both ribonucleotides and deoxyribonucleotides, natural andunnatural) and the set of pentoses and hexoses. As used herein, monomerrefers to any member of a basis set for synthesis of a larger molecule.A selected set of monomers forms a basis set of monomers. For example,the basis set of nucleotides includes A, T (or U), G and C. In anotherexample, dimers of the 20 naturally occurring L-amino acids form a basisset of 400 monomers for synthesis of polypeptides. Different basis setsof monomers may be used in any of the successive steps in the synthesisof a polymer. Furthermore, each of the sets may include protectedmembers which are modified after synthesis.

The term “mRNA” or sometimes refer by “mRNA transcripts” as used herein,include, but not limited to pre-mRNA transcript(s), transcriptprocessing intermediates, mature mRNA(s) ready for translation andtranscripts of the gene or genes, or nucleic acids derived from the mRNAtranscript(s). Transcript processing may include splicing, editing anddegradation. As used herein, a nucleic acid derived from an mRNAtranscript refers to a nucleic acid for whose synthesis the mRNAtranscript or a subsequence thereof has ultimately served as a template.Thus, a cDNA reverse transcribed from an mRNA, an RNA transcribed fromthat cDNA, a DNA amplified from the cDNA, an RNA transcribed from theamplified DNA, etc., are all derived from the mRNA transcript anddetection of such derived products is indicative of the presence and/orabundance of the original transcript in a sample. Thus, mRNA derivedsamples include, but are not limited to, mRNA transcripts of the gene orgenes, cDNA reverse transcribed from the mRNA, cRNA transcribed from thecDNA, DNA amplified from the genes, RNA transcribed from amplified DNA,and the like.

The term “nucleic acid library” or sometimes refer by “array” as usedherein refers to an intentionally created collection of nucleic acidswhich can be prepared either synthetically or biosynthetically andscreened for biological activity in a variety of different formats (forexample, libraries of soluble molecules; and libraries of oligostethered to resin beads, silica chips, or other solid supports).Additionally, the term “array” is meant to include those libraries ofnucleic acids which can be prepared by spotting nucleic acids ofessentially any length (for example, from 1 to about 1000 nucleotidemonomers in length) onto a substrate. The term “nucleic acid” as usedherein refers to a polymeric form of nucleotides of any length, eitherribonucleotides, deoxyribonucleotides or peptide nucleic acids (PNAs),that comprise purine and pyrimidine bases, or other natural, chemicallyor biochemically modified, non-natural, or derivatized nucleotide bases.The backbone of the polynucleotide can comprise sugars and phosphategroups, as may typically be found in RNA or DNA, or modified orsubstituted sugar or phosphate groups. A polynucleotide may comprisemodified nucleotides, such as methylated nucleotides and nucleotideanalogs. The sequence of nucleotides may be interrupted bynon-nucleotide components. Thus the terms nucleoside, nucleotide,deoxynucleoside and deoxynucleotide generally include analogs such asthose described herein. These analogs are those molecules having somestructural features in common with a naturally occurring nucleoside ornucleotide such that when incorporated into a nucleic acid oroligonucleoside sequence, they allow hybridization with a naturallyoccurring nucleic acid sequence in solution. Typically, these analogsare derived from naturally occurring nucleosides and nucleotides byreplacing and/or modifying the base, the ribose or the phosphodiestermoiety. The changes can be tailor made to stabilize or destabilizehybrid formation or enhance the specificity of hybridization with acomplementary nucleic acid sequence as desired.

The term “nucleic acids” as used herein may include any polymer oroligomer of pyrimidine and purine bases. In one aspect “nucleic acids”include cytosine, thymine, and uracil, and adenine and guanine,respectively. See Albert L. Lehninger, Principles of Biochemistry, at793-800 (Worth Pub. 1982). Indeed, the present invention contemplatesany deoxyribonucleotide, ribonucleotide or peptide nucleic acidcomponent, and any chemical variants thereof, such as methylated,hydroxymethylated or glucosylated forms of these bases, and the like.The polymers or oligomers may be heterogeneous or homogeneous incomposition, and may be isolated from naturally-occurring sources or maybe artificially or synthetically produced. In addition, the nucleicacids may be DNA or RNA, or a mixture thereof, and may exist permanentlyor transitionally in single-stranded or double-stranded form, includinghomoduplex, heteroduplex, and hybrid states.

The term “oligonucleotide” or sometimes refer by “polynucleotide” asused herein refers to a nucleic acid ranging from at least 2, at least8, and at least 20 nucleotides in length or a compound that specificallyhybridizes to a polynucleotide. Polynucleotides of the present inventioninclude sequences of deoxyribonucleic acid (DNA) or ribonucleic acid(RNA) which may be isolated from natural sources, recombinantly producedor artificially synthesized and mimetics thereof. A further example of apolynucleotide of the present invention may be peptide nucleic acid(PNA). The invention also encompasses situations in which there is anontraditional base pairing such as Hoogsteen base pairing which hasbeen identified in certain tRNA molecules and postulated to exist in atriple helix. “Polynucleotide” and “oligonucleotide” are usedinterchangeably in this application.

The term “primer” as used herein refers to a single-strandedoligonucleotide capable of acting as a point of initiation fortemplate-directed DNA synthesis under suitable conditions for example,buffer and temperature, in the presence of four different nucleosidetriphosphates and an agent for polymerization, such as, for example, DNAor RNA polymerase or reverse transcriptase. The length of the primer, inany given case, depends on, for example, the intended use of the primer,and generally ranges from 15 to 30 nucleotides. Short primer moleculesgenerally require cooler temperatures to form sufficiently stable hybridcomplexes with the template. A primer need not reflect the exactsequence of the template but must be sufficiently complementary tohybridize with such template. The primer site is the area of thetemplate to which a primer hybridizes. The primer pair is a set ofprimers including a 5′ upstream primer that hybridizes with the 5′ endof the sequence to be amplified and a 3′ downstream primer thathybridizes with the complement of the 3′ end of the sequence to beamplified.

The term “probe” as used herein refers to a surface-immobilized orfree-in-solution molecule that can be recognized by a particular target.U.S. Pat. No. 6,582,908 provides an example of arrays having allpossible combinations of nucleic acid-based probes having a length of 10bases, and 12 bases or more. In one embodiment, a probe may consist ofan open circle molecule, comprising a nucleic acid having left and rightarms whose sequences are complementary to the target, and separated by alinker region. Open circle probes are described in, for instance, U.S.Pat. No. 6,858,412, and Hardenbol et al., Nat. Biotechnol., 21(6):673(2003). In another embodiment, a probe, such as a nucleic acid, may beattached to a microparticle carrying a distinguishable code. Examples ofencoded microparticles, methods of making the same, methods forfabricating the microparticles, methods and systems for detectingmicroparticles, and the methods and systems for using microparticles aredescribed in U.S. Patent Application Publication Nos. 20080038559,20070148599, and PCT Application No. WO 2007/081410. Each of which ishereby incorporated by reference in its entirety for all purposes.Examples of nucleic acid probe sequences that may be investigated bythis invention include, but are not restricted to, those that arecomplementary to genes encoding agonists and antagonists for cellmembrane receptors, toxins and venoms, viral epitopes, hormones (forexample, opioid peptides, steroids, etc.), hormone receptors, peptides,enzymes, enzyme substrates, cofactors, drugs, lectins, sugars,oligonucleotides, nucleic acids, oligosaccharides, proteins, andmonoclonal antibodies.

The term “protecting group” as used herein refers to a material which ischemically bound to a reactive functional group on a monomer unit orpolymer and which protective group may be removed upon selectiveexposure to an activator such as a chemical activator, or anotheractivator, such as electromagnetic radiation or light, especiallyultraviolet and visible light. Protecting groups that are removable uponexposure to electromagnetic radiation, and in particular light, aretermed “photolabile protecting groups.”

The term “solid support”, “support”, and “substrate” as used herein areused interchangeably and refer to a material or group of materialshaving a rigid or semi-rigid surface or surfaces. In many embodiments,at least one surface of the solid support will be substantially flat,although in some embodiments it may be desirable to physically separatesynthesis regions for different compounds with, for example, wells,trenches, grooves, raised regions, pins, etched trenches, or the like.Solid supports used in the present invention include any of a variety offixed organizational support matrices. According to other embodiments,the solid support(s) will take the form of slides, solid chips, beads,resins, gels, microspheres, or other geometric configurations. (See,U.S. Pat. No. 5,744,305, for exemplary substrates). Additionally, thesolid supports may be, for example, biological, nonbiological, organic,inorganic, or a combination thereof, and may be in forms includingparticles, strands, gels, sheets, tubing, spheres, containers,capillaries, pads, slices, films, plates, and slides depending upon theintended use.

The term “target” as used herein refers to a molecule that has anaffinity for a given probe. Targets may be naturally-occurring orman-made molecules. Also, they can be employed in their unaltered stateor as aggregates with other species. Targets may be attached, covalentlyor noncovalently, to a binding member, either directly or via a specificbinding substance. Examples of targets which can be employed by thisinvention include, but are not restricted to, antibodies, cell membranereceptors, monoclonal antibodies and antisera reactive with specificantigenic determinants (such as on viruses, cells or other materials),drugs, oligonucleotides, nucleic acids, peptides, cofactors, lectins,sugars, polysaccharides, cells, cellular membranes, and organelles.Targets are sometimes referred to in the art as anti-probes. As the termtargets is used herein, no difference in meaning is intended. A “ProbeTarget Pair” is formed when two macromolecules have combined throughmolecular recognition to form a complex.

The term “wafer” as used herein refers to a substrate having surface towhich a plurality of polymers such as oligonucleotide, ribonucleotides,deoxyribonucleotides, peptides, peptide nucleic acids (PNAs), thatcomprise purine and pyrimidine bases, or other natural, chemically orbiochemically modified, non-natural, or derivatized nucleotide bases,that can be bound and thereafter may be diced.

B. Embodiments of the Present Invention

Embodiments of an imaging system and methods of detection are describedherein in which data is acquired by scanning probe arrays comprisingprobe features. In particular, embodiments are described that comprise aCCD based optical architecture using a combination of LED light sourcesto perform the functions of automatic focus and excitation offluorescent molecules. Details are described in U.S. patent applicationSer. No. 11/379,641 filed on Apr. 21, 2006, which is hereby incorporatedby reference herein in its entirety for all purposes.

Probe Array 140:

An illustrative example of probe array 140 is provided in FIGS. 1, 2,and 3. Descriptions of probe arrays are provided above with respect to“Nucleic Acid Probe arrays” and other related disclosure. In variousimplementations, probe array 140 may be disposed in a cartridge orhousing such as, for example, the GENECHIP® probe array available fromAffymetrix, Inc. of Santa Clara Calif. Examples of probe arrays andassociated cartridges or housings may be found in U.S. Pat. Nos.5,945,334, 6,287,850, 6,399,365, 6,551,817, each of which is also herebyincorporated by reference herein in its entirety for all purposes. Inaddition, some embodiments of probe array 140 may be associated withpegs or posts, where for instance probe array 140 may be affixed viagluing, welding, or other means known in the related art to the peg orpost that may be operatively coupled to a tray, strip or other type ofsimilar substrate. Examples with embodiments of probe array 140associated with pegs or posts may be found in U.S. patent applicationSer. No. 10/826,577, titled “Immersion Array Plates for InterchangeableMicrotiter Well Plates”, filed Apr. 16, 2004, which is herebyincorporated by reference herein in its entirety for all purposes.

Server 120:

FIG. 1 shows a typical configuration of a server computer connected to aworkstation computer via a network. In some implementations any functionascribed to Server 120 may be carried out by one or more othercomputers, and/or the functions may be performed in parallel by a groupof computers.

Typically, server 120 is a network-server class of computer designed forservicing a number of workstations or other computer platforms over anetwork. However, server 120 may be any of a variety of types ofgeneral-purpose computers such as a personal computer, workstation, mainframe computer, or other computer platform now or later developed.Server 120 typically includes known components such as a processor, anoperating system, a system memory, memory storage devices, andinput-output controllers. It will be understood by those skilled in therelevant art that there are many possible configurations of thecomponents of server 120 that may typically include cache memory, a databackup unit, and many other devices. Similarly, many hardware andassociated software or firmware components may be implemented in anetwork server. For example, components to implement one or morefirewalls to protect data and applications, uninterruptible powersupplies, LAN switches, web-server routing software, and many othercomponents. Those of ordinary skill in the art will readily appreciatehow these and other conventional components may be implemented.

Server 120 may employ one or more processing elements that may, forinstance, include multiple processors; e.g., multiple Intel® Xeon™ 3.2GHz processors. As further examples, the processing elements may includeone or more of a variety of other commercially available processors suchas Itanium® 2 64-bit processors or Pentium® processors from Intel,SPARC® processors made by Sun Microsystems, Opteron™ processors fromAdvanced Micro Devices, or other processors that are or will becomeavailable. Some embodiments of processing elements may also include whatare referred to as Multi-core processors and/or be enabled to employparallel processing technology in a single or multi-core configuration.In addition, those of ordinary skill in the related will appreciate thatprocessing elements may be configured in what is generally referred toas a 32 or 64 bit architecture, or other architectural configurationsnow known or that may be developed in the future.

The processing elements execute the operating system, which may be, forexample, a Windows®-type operating system (such as Windows® XPProfessional (which may include a version of Internet Information Server(IIS))) from the Microsoft Corporation; the Mac OS X Server operatingsystem from Apple Computer Corp.; the Solaris operating system from SunMicrosystems, the Tru64 Unix from Compaq, other Unix® or Linux-typeoperating systems available from many vendors or open sources; anotheror a future operating system; or some combination thereof. The operatingsystem interfaces with firmware and hardware in a well-known manner, andfacilitates the processor in coordinating and executing the functions ofvarious computer programs that may be written in a variety ofprogramming languages. The operating system, typically in cooperationwith the processor, coordinates and executes functions of the othercomponents of server 120. The operating system also provides scheduling,input-output control, file and data management, memory management, andcommunication control and related services, all in accordance with knowntechniques.

The system memory may be any of a variety of known or future memorystorage devices. Examples include any commonly available random accessmemory (RAM), magnetic medium such as a resident hard disk or tape, anoptical medium such as a read and write compact disc, or other memorystorage device. The memory storage device may be any of a variety ofknown or future devices, including a compact disk drive, a tape drive, aremovable hard disk drive, USB or flash drive, or a diskette drive. Suchtypes of memory storage device typically read from, and/or write to, aprogram storage medium (not shown) such as, respectively, a compactdisk, magnetic tape, removable hard disk, USB or flash drive, or floppydiskette. Any of these program storage media, or others now in use orthat may later be developed, may be considered a computer programproduct. As will be appreciated, these program storage media typicallystore a computer software program and/or data. Computer softwareprograms, also called computer control logic, typically are stored inthe system memory and/or the program storage device used in conjunctionwith the memory storage device.

In some embodiments, a computer program product is described comprisinga computer usable medium having control logic (computer softwareprogram, including program code) stored therein. The control logic, whenexecuted by the processor, causes the processor to perform functionsdescribed herein. In other embodiments, some functions are implementedprimarily in hardware using, for example, a hardware state machine.Implementation of the hardware state machine so as to perform thefunctions described herein will be apparent to those skilled in therelevant arts.

The input-output controllers could include any of a variety of knowndevices for accepting and processing information from a user, whether ahuman or a machine, whether local or remote. Such devices include, forexample, modem cards, network interface cards, sound cards, or othertypes of controllers for any of a variety of known input or outputdevices. In the illustrated embodiment, the functional elements ofserver 120 communicate with each other via a system bus. Some of thesecommunications may be accomplished in alternative embodiments usingnetwork or other types of remote communications.

As will be evident to those skilled in the relevant art, a serverapplication if implemented in software, may be loaded into the systemmemory and/or the memory storage device through one of the inputdevices. All or portions of these loaded elements may also reside in aread-only memory or similar device of the memory storage device, suchdevices not requiring that the elements first be loaded through theinput devices. It will be understood by those skilled in the relevantart that any of the loaded elements, or portions of them, may be loadedby the processor in a known manner into the system memory, or cachememory (not shown), or both, as advantageous for execution.

Scanner System 100:

Labeled targets hybridized to probe arrays may be detected using variousdevices, sometimes referred to as scanners, as described above withrespect to methods and apparatus for signal detection. An illustrativedevice is shown in FIG. 1 as scanner 100, that may incorporate a varietyof optical elements such as the example illustrated in FIG. 3 thatincludes a plurality of optical elements associated with scanner opticsand detectors 200. For example, scanners image the targets by detectingfluorescent or other emissions from labels associated with targetmolecules, or by detecting transmitted, reflected, or scatteredradiation. A typical scheme employs optical and other elements toprovide excitation light and to selectively collect the emissions.

For example, scanner 100 provides a signal representing the intensities(and possibly other characteristics, such as color that may beassociated with a detected wavelength) of the detected emissions orreflected wavelengths of light, as well as the locations on thesubstrate where the emissions or reflected wavelengths were detected.Typically, the signal includes intensity information corresponding toelemental sub-areas of the scanned substrate. The term “elemental” inthis context means that the intensities, and/or other characteristics,of the emissions or reflected wavelengths from this area each arerepresented by a single value. When displayed as an image for viewing orprocessing, elemental picture elements, or pixels, often represent thisinformation. Thus, in the present example, a pixel may have a singlevalue representing the intensity of the elemental sub-area of thesubstrate from which the emissions or reflected wavelengths werescanned. The pixel may also have another value representing anothercharacteristic, such as color, positive or negative image, or other typeof image representation. The size of a pixel may vary in differentembodiments and could include a 2.5 microns, 1.5 microns, 1.0 micron, orsub-micron pixel size. Two examples where the signal may be incorporatedinto data are data files in the form *.dat or *.tif as generatedrespectively by AFFYMETRIX® Microarray Suite (described in U.S. patentapplication Ser. No. 10/219,882, which is hereby incorporated byreference herein in its entirety for all purposes) or AffymetrixGENECHIP® Operating Software (described in U.S. patent application Ser.No. 10/764,663, which is hereby incorporated by reference herein in itsentirety for all purposes) or AFFYMETRIX® command-control Software(described in U.S. patent application Ser. No. 11/279,068, which ishereby incorporated by reference herein in its entirety for allpurposes) based on images scanned from GENECHIP® arrays, and AFFYMETRIX®Jaguar™ software (described in U.S. patent application Ser. No.09/682,071, which is hereby incorporated by reference herein in itsentirety for all purposes) based on images scanned from spotted arrays.Examples of scanner systems that may be implemented with embodiments ofthe present invention include U.S. patent application Ser. Nos.10/389,194; 10/913,102, both of which are incorporated by referenceabove; and U.S. patent application Ser. No. 10/846,261, titled “System,Method, and Product for Providing A Wavelength-Tunable Excitation Beam”,filed May 13, 2004; and U.S. patent application Ser. No. 11/260,617,titled “System, Method and Product for Multiple Wavelength DetectionUsing Single Source Excitation”, filed Oct. 27, 2005, each of which ishereby incorporated by reference herein in its entirety for allpurposes.

Embodiments of the scanner 100 may employ a CCD (Charge Coupled Device)architecture using a CCD or cooled CCD cameras with a wide field ofview. For example, a CCD based optical architecture for acquiring imagesfrom probe array 140 is described in greater detail below with respectto scanner optics and detectors 200.

Computer 150:

An illustrative example of computer 150 is provided in FIG. 1 and alsoin greater detail in FIG. 2. Computer 150 may be any type of computerplatform such as a workstation, a personal computer, a server, or anyother present or future computer. Computer 150 typically includes knowncomponents such as a processor 255, an operating system 260, systemmemory 270, memory storage devices 281, and input-output controllers275, input devices 240, and display/output devices 245. Display/OutputDevices 245 may include display devices that provides visualinformation, this information typically may be logically and/orphysically organized as an array of pixels. A Graphical user interface(GUI) controller may also be included that may comprise any of a varietyof known or future software programs for providing graphical input andoutput interfaces such as for instance GUI's 246. For example, GUI's 246may provide one or more graphical representations to a user, such asuser 101, and also be enabled to process user inputs via GUI's 246 usingmeans of selection or input known to those of ordinary skill in therelated art.

It will be understood by those of ordinary skill in the relevant artthat there are many possible configurations of the components ofcomputer 150 and that some components that may typically be included incomputer 150 are not shown, such as cache memory, a data backup unit,and many other devices. Processor 255 may be a commercially availableprocessor such as an Itanium® or Pentium® processor made by IntelCorporation, a SPARC® processor made by Sun Microsystems, an Athalon™ orOpteron™ processor made by AMD corporation, or it may be one of otherprocessors that are or will become available. Some embodiments ofprocessor 255 may also include what are referred to as Multi-coreprocessors and/or be enabled to employ parallel processing technology ina single or multi-core configuration. For example, a multi-corearchitecture typically comprises two or more processor “executioncores”. In the present example each execution core may perform as anindependent processor that enables parallel execution of multiplethreads. In addition, those of ordinary skill in the related willappreciate that processor 255 may be configured in what is generallyreferred to as 32 or 64 bit architectures, or other architecturalconfigurations now known or that may be developed in the future.

Processor 255 executes operating system 260, which may be, for example,a Windows®-type operating system (such as Windows® XP) from theMicrosoft Corporation; the Mac OS X operating system from Apple ComputerCorp. (such as 7.5 Mac OS X v10.4 “Tiger” or 7.6 Mac OS X v10.5“Leopard” operating systems); a Unix® or Linux-type operating systemavailable from many vendors or what is referred to as an open source;another or a future operating system; or some combination thereof.Operating system 260 interfaces with firmware and hardware in awell-known manner, and facilitates processor 255 in coordinating andexecuting the functions of various computer programs that may be writtenin a variety of programming languages. Operating system 260, typicallyin cooperation with processor 255, coordinates and executes functions ofthe other components of computer 150. Operating system 260 also providesscheduling, input-output control, file and data management, memorymanagement, and communication control and related services, all inaccordance with known techniques.

System memory 270 may be any of a variety of known or future memorystorage devices. Examples include any commonly available random accessmemory (RAM), magnetic medium such as a resident hard disk or tape, anoptical medium such as a read and write compact disc, or other memorystorage device. Memory storage devices 281 may be any of a variety ofknown or future devices, including a compact disk drive, a tape drive, aremovable hard disk drive, USB or flash drive, or a diskette drive. Suchtypes of memory storage devices 281 typically read from, and/or writeto, a program storage medium (not shown) such as, respectively, acompact disk, magnetic tape, removable hard disk, USB or flash drive, orfloppy diskette. Any of these program storage media, or others now inuse or that may later be developed, may be considered a computer programproduct. As will be appreciated, these program storage media typicallystore a computer software program and/or data. Computer softwareprograms, also called computer control logic, typically are stored insystem memory 270 and/or the program storage device used in conjunctionwith memory storage device 281.

In some embodiments, a computer program product is described comprisinga computer usable medium having control logic (computer softwareprogram, including program code) stored therein. The control logic, whenexecuted by processor 255, causes processor 255 to perform functionsdescribed herein. In other embodiments, some functions are implementedprimarily in hardware using, for example, a hardware state machine.Implementation of the hardware state machine so as to perform thefunctions described herein will be apparent to those skilled in therelevant arts.

Input-output controllers 275 could include any of a variety of knowndevices for accepting and processing information from a user, whether ahuman or a machine, whether local or remote. Such devices include, forexample, modem cards, wireless cards, network interface cards, soundcards, or other types of controllers for any of a variety of known inputdevices. Output controllers of input-output controllers 275 couldinclude controllers for any of a variety of known display devices forpresenting information to a user, whether a human or a machine, whetherlocal or remote. In the illustrated embodiment, the functional elementsof computer 150 communicate with each other via system bus 290. Some ofthese communications may be accomplished in alternative embodimentsusing network or other types of remote communications.

As will be evident to those skilled in the relevant art, instrumentcontrol and image processing applications 272, if implemented insoftware, may be loaded into and executed from system memory 270 and/ormemory storage device 281. All or portions of applications 272 may alsoreside in a read-only memory or similar device of memory storage device281, such devices not requiring that applications 272 first be loadedthrough input-output controllers 275. It will be understood by thoseskilled in the relevant art that applications 272, or portions of it,may be loaded by processor 255 in a known manner into system memory 270,or cache memory (not shown), or both, as advantageous for execution.Also illustrated in FIG. 2 are library files 274, calibration data 276,and experiment data 277, and internet client 279 stored in system memory270. For example, experiment data 277 could include data related to oneor more experiments or assays such as excitation wavelength ranges,emission wavelength ranges, extinction coefficients and/or associatedexcitation power level values, or other values associated with one ormore fluorescent labels. Additionally, internet client 279 may includean application enabled to accesses a remote service on another computerusing a network that may for instance comprise what are generallyreferred to as “Web Browsers”. In the present example some commonlyemployed web browsers include Netscape® 8.0 available from NetscapeCommunications Corp., Microsoft® Internet Explorer 6 with SP1 availablefrom Microsoft Corporation, Mozilla Firefox® 1.5 from the MozillaCorporation, Safari 2.0 from Apple Computer Corp., or other type of webbrowser currently known in the art or to be developed in the future.Also, in the same or other embodiments internet client 279 may include,or could be an element of, specialized software applications enabled toaccess remote information via a network such as network 125 such as, forinstance, the GENECHIP® Data Analysis Software (GDAS) package orChromosome Copy Number Tool (CNAT) both available from Affymetrix, Inc.of Santa Clara Calif. that are each enabled to access information fromremote sources, and in particular probe array annotation informationfrom the NetAffx™ web site hosted on one or more servers provided byAffymetrix, Inc.

Network 125 may include one or more of the many various types ofnetworks well known to those of ordinary skill in the art. For example,network 125 may include a local or wide area network that employs whatis commonly referred to as a TCP/IP protocol suite to communicate, thatmay include a network comprising a worldwide system of interconnectedcomputer networks that is commonly referred to as the internet, or couldalso include various intranet architectures. Those of ordinary skill inthe related arts will also appreciate that some users in networkedenvironments may employ what are generally referred to as “firewalls”(also sometimes referred to as Packet Filters, or Border ProtectionDevices) to control information traffic to and from hardware and/orsoftware systems. For example, firewalls may comprise hardware orsoftware elements or some combination thereof and are typically designedto enforce security policies put in place by users, such as for instancenetwork administrators, etc.

Instrument control and image processing applications 272: Instrumentcontrol and image processing applications 272 may comprise any of avariety of known or future image processing applications. Some examplesof known instrument control and image processing applications includethe AFFYMETRIX® Microarray Suite, and Affymetrix GENECHIP® OperatingSoftware (hereafter referred to as GCOS) applications. Typically,embodiments of applications 272 may be loaded into system memory 270and/or memory storage device 281 through one of input devices 240.

Some embodiments of applications 272 include executable code beingstored in system memory 270. For example, the described embodiments ofapplications 272 may, for example, include the AFFYMETRIX®Command-Console™ software. Embodiments of applications 272 mayadvantageously provide what is referred to as a modular interface forone or more computers or workstations and one or more servers, as wellas one or more instruments. The term “modular” as used herein generallyrefers to elements that may be integrated to and interact with a coreelement in order to provide a flexible, updateable, and customizableplatform. For example, as will be described in greater detail belowapplications 272 may comprise a “core” software element enabled tocommunicate and perform primary functions necessary for any instrumentcontrol and image processing application. Such primary functionality mayinclude communication over various network architectures, or dataprocessing functions such as processing raw intensity data into a .datfile. In the present example, modular software elements, such as forinstance what may be referred to as a plug-in module, may be interfacedwith the core software element to perform more specific or secondaryfunctions, such as for instance functions that are specific toparticular instruments. In particular, the specific or secondaryfunctions may include functions customizable for particular applicationsdesired by user 101. Further, integrated modules and the core softwareelement are considered to be a single software application, and referredto as applications 272.

In the presently described implementation, applications 272 maycommunicate with, and receive instruction or information from, orcontrol one or more elements or processes of one or more servers, one ormore workstations, and one or more instruments. Also, embodiments ofserver 120 or computer 150 with an implementation of applications 272stored thereon could be located locally or remotely and communicate withone or more additional servers and/or one or more othercomputers/workstations or instruments.

In some embodiments, applications 272 may be capable of dataencryption/decryption functionality. For example, it may be desirable toencrypt data, files, information associated with GUI's 246, or otherinformation that may be transferred over network 125 to one or moreremote computers or servers for data security and confidentialitypurposes. For example, some embodiments of probe array 140 may beemployed for diagnostic purposes where the data may be associated with apatient and/or a diagnosis of a disease or medical condition. It isdesirable in many applications to protect the data using encryption forconfidentiality of patient information. In addition, one-way encryptiontechnologies may be employed in situations where access should belimited to only selected parties such as a patient and their physician.In the present example, only the selected parties have the key todecrypt or associate the data with the patient. In some applications,the one-way encrypted data may be stored in one or more public databasesor repositories where even the curator of the database or repositorywould be unable to associate the data with the user or otherwise decryptthe information. The described encryption functionality may also haveutility in clinical trial applications where it may be desirable toisolate one or more data elements from each other for the purpose ofconfidentiality and/or removal of experimental biases.

Various embodiments of applications 272 may provide one or moreinteractive graphical user interfaces that allows user 101 to makeselections based upon information presented in an embodiment of GUI 246.Those of ordinary skill will recognize that embodiments of GUI 246 maybe coded in various language formats such as an HTML, XHTML, XML,javascript, Jscript, or other language known to those of ordinary skillin the art used for the creation or enhancement of “Web Pages” viewableand compatible with internet client 279. For example, internet client379 may include various internet browsers such as Microsoft InternetExplorer, Netscape Navigator, Mozilla Firefox, Apple Safari, or otherbrowsers known in the art. Applications of GUI's 246 viewable via one ormore browsers may allow user 101 complete remote access to data,management, and registration functions without any other specializedsoftware elements. Applications 272 may provide one or moreimplementations of interactive GUI's 246 that allow user 101 to selectfrom a variety of options including data selection, experimentparameters, calibration values, and probe array information within theaccess to data, management, and registration functions.

In some embodiments, applications 272 may be capable of running onoperating systems in a non-English format, where applications 272 canaccept input from user 101 in various non-English language formats suchas Chinese, French, Spanish etc., and output information to user 101 inthe same or other desired language output. For example, applications 272may present information to user 101 in various implementations of GUI246 in a language output desired by user 101, and similarly receiveinput from user 101 in the desired language. In the present example,applications 272 is internationalized such that it is capable ofinterpreting the input from user 101 in the desired language where theinput is acceptable input with respect to the functions and capabilitiesof applications 272.

Embodiments of applications 272 also include instrument controlfeatures, where the control functions of individual types or specificinstruments such as scanner 100, an autoloader, or fluid handling systemmay be organized as plug-in type modules to applications 272. Forexample, each plug-in module may be a separate component and may providedefinition of the instrument control features to applications 272. Asdescribed above, each plug-in module is functionally integrated withapplications 272 when stored in system memory 270 and thus reference toapplications 272 includes any integrated plug-in modules. In the presentexample, each instrument may have one or more associated embodiments ofplug-in module that for instance may be specific to model of instrument,revision of instrument firmware or scripts, number and/or configurationof instrument embodiment, etc. Further, multiple embodiments of plug-inmodule for the same instrument such as scanner 100 may be stored insystem memory 270 for use by applications 272, where user 101 may selectthe desired embodiment of module to employ, or alternatively such aselection of module may be defined by data encoded directly in a machinereadable identifier or indirectly via the array file, library files,experiments files and so on.

The instrument control features may include the control of one or moreelements of one or more instruments that could, for instance, includeelements of a hybridization device, fluid handling system, autoloader,and scanner 100. The instrument control features may also be capable ofreceiving information from the one more instruments that could includeexperiment or instrument status, process steps, or other relevantinformation. The instrument control features could, for example, beunder the control of or an element of the interface of applications 272.In some embodiments, a user may input desired control commands and/orreceive the instrument control information via one of GUI's 246.Additional examples of instrument control via a GUI or other interfaceis provided in U.S. patent application Ser. No. 10/764,663, titled“System, Method and Computer Software Product for Instrument Control,Data Acquisition, Analysis, Management and Storage”, filed Jan. 26,2004, which is hereby incorporated by reference herein in its entiretyfor all purposes.

In some embodiments, applications 272 may employ what may referred to asan “array file” that comprises data employed for various processingfunctions of images by applications 272 as well as other relevantinformation. Generally it is desirable to consolidate elements of dataor metadata related to an embodiment of probe array 140, experiment,user, or some combination thereof, to a single file that is notduplicated (i.e. as embodiments of .dat file may be in certainapplications), where duplication may sometimes be a source of error. Theterm “metadata” as used herein generally refers to data about data. Itmay also be desirable in some embodiments to restrict or prohibit theability to overwrite data in the array file. New information may beappended to the array file rather than deleting or overwritinginformation, providing the benefit of traceability and data integrity(i.e. as may be required by some regulatory agencies). For example, anarray file may be associated with one or more implementations of anembodiment of probe array 140, where the array file acts to unify dataacross a set of probe arrays 140. The array file may be created byapplications 272 via a registration process, where user 101 inputs datainto applications 272 via one or more of GUI's 246. In the presentexample, the array file may be associated by user 101 with a customidentifier that could include a machine readable identifier such as themachine readable identifiers described in greater detail below.Alternatively, applications 272 may create an array file andautomatically associate the array file with a machine readableidentifier that identifies an embodiment of probe array 140 (i.e.relationship between the machine readable identifier and probe array 140may be assigned by a manufacturer). Applications 272 may employ variousdata elements for the creation or update of the array file from one ormore library files, such as library files 274 or other library files.

Alternatively, the array file may comprise pointers to one or moreadditional data files comprising data related to an associatedembodiment of probe array 140. For example, the manufacturer of probearray 140 or other user may provide library files 274 or other filesthat define characteristics such as probe identity; dimension andpositional location (i.e. with respect to some fiducial reference orcoordinate system) of the active area of probe array 140; variousexperimental parameters; instrument control parameters; or other typesof useful information. In addition, the array file may also contain oneor more metadata elements that could include one or more of a uniqueidentifier for the array file, human readable form of a machine readableidentifier, or other metadata elements. In addition, applications 272may store data (i.e. as metadata, or stored data) that includes sampleidentifiers, array names, user parameters, event logs that may forinstance include a value identifying the number of times an array hasbeen scanned, relationship histories such as for instance therelationship between each .cel file and the one or more .dat files thatwere employed to generate the .cel file, and other types of data usefulin for processing and data management.

For example, user 101 and/or automated data input devices or programs(not shown) may provide data related to the design or conduct ofexperiments. User 101 may specify an Affymetrix catalogue or custom chiptype (e.g., Human Genome U133 plus 2.0 chip) either by selecting from apredetermined list presented in one or more of GUI's 246 or by scanninga bar code, Radio Frequency Identification (RFID), magnetic strip, orother means of electronic identification related to a chip to read itstype, part no., array identifier, etc. Applications 272 may associatethe chip type, part numbers, array identifier with various scanningparameters stored in data tables or library files, such as library files274 of computer 150, including the area of the chip that is to bescanned, the location of chrome elements or other features on the chipused for auto-focusing, the wavelength or intensity/power of excitationlight to be used in reading the chip, and so on. Also, some embodimentsof applications 272 may encode array files in a binary type format thatmay minimize the possibility of data corruption. However, applications272 may be further enabled to export an array file in a number ofdifferent formats.

Also, in the same or alternative embodiments, applications 272 maygenerate or access what may be referred to as a “plate” file. The platefile may encode one or more data elements such as pointers to one ormore array files, and may include pointers to a plurality of arrayfiles.

In some embodiments, raw image data is acquired from scanner 100 andoperated upon by applications 272 to generate intermediate results. Forexample, raw intensity data, represented as detected signal 292 of FIG.2, acquired from scanner 100 may be directed to a .dat file generatorand written to data files (*.dat) that comprises an intensity value foreach pixel of data acquired from a scan of an embodiment of probe array140. In the same or alternative embodiments it may be advantageous toscan sub areas (that may be referred to as sub arrays or sections of thearray) of probe array 140 where detected signal 292 for each sub areascanned may be written to an individual embodiment of a .dat file.Continuing with the present example, applications 272 may also encode aunique identifier for each .dat file as well as a pointer to anassociated embodiment of an array file as metadata into each .dat filegenerated. The term “pointer” as used herein generally refers to aprogramming language datatype, variable, or data object that referencesanother data object, datatype, variable, etc. using a memory address oridentifier of the referenced element in a memory storage device such asin system memory 270. In some embodiments the pointers comprise theunique identifiers of the files that are the subject of the pointing,such as for instance the pointer in a .dat file comprises the uniqueidentifier of the array file. Additional examples of the generation andimage processing of sub arrays is described in U.S. patent applicationSer. No. 11/289,975, titled “System, Method, and Product for AnalyzingImages Comprising Small Feature Sizes”, filed Nov. 30, 2005, which ishereby incorporated by reference herein in its entirety for all purpose.

Also, applications 272 may also include a .cel file generator that mayproduce one or more .cel files (*.cel) by processing each .dat file.Alternatively, some embodiments of .cel file generator may produce asingle .cel file from processing multiple .dat files such as with theexample of processing multiple sub-arrays described above. Similar tothe .dat file described above each embodiment of .cel file 425 may alsoinclude one or more metadata elements. For example, applications 272 mayencode a unique identifier for each .cel file as well as a pointer to anassociated array file and/or the one or more .dat files used to producethe .cel file.

Each .cel file contains, for each probe feature scanned by scanner 100,a single value representative of the intensities of pixels measured byscanner 100 for that probe. For example, this value may include ameasure of the abundance of tagged mRNA's present in the target thathybridized to the corresponding probe. Many such mRNA's may be presentin each probe, as a probe on a GENECHIP® probe array may include, forexample, millions of oligonucleotides designed to detect the mRNA's.Alternatively, the value may include a measure related to the sequencecomposition of DNA or other nucleic acid detected by the probes of aGENECHIP® probe array. As described above, applications 272 receivesimage data derived from probe array 140 using scanner 100 and generatesa .dat file that is then processed by applications 272 to produce a .celintensity file, where applications 272 may utilize information from anarray file in the image processing function. For instance, the .cel filegenerator may perform what is referred to as grid placement methods onthe image data in each .dat file using data elements such as dimensioninformation to determine and define the positional location of probefeatures in the image. Typically, the .cel file generator associateswhat may be referred to as a grid with the image data in a .dat file forthe purpose of determining the positional relationship of probe featuresin the image with the known positions and identities of the probefeatures. The accurate registration of the grid with the image isimportant for the accuracy of the information in the resulting .celfile. Also, some embodiments of .cel file generator may provide user 101with a graphical representation of a grid aligned to image data from aselected .dat file in an implementation of GUI 246, and further enableuser 101 to manually refine the position of the grid placement usingmethods commonly employed such as placing a cursor over the grid,selecting such as by holding down a button on a mouse, and dragging thegrid to a positional relationship with the image. Applications 272 maythen perform methods sometimes referred to as “feature extraction” toassign a value of intensity for each probe represented in the image asan area defined by the boundary lines of the grid. Examples of gridregistration, methods of positional refinement, and feature extractionare described in U.S. Pat. Nos. 6,090,555, 6,611,767, 6,829,376, andU.S. patent application Ser. Nos. 10/391,882, and 10/197,369, each ofwhich is hereby incorporated by reference herein in their entirety forall purposes.

As noted, another file that may be generated by applications 272 is .chpfile 435 using a .chp file generator. For example, each .chp file isderived from analysis of a .cel file combined in some cases withinformation derived from an array file, other lab data and/or libraryfiles 274 that specify details regarding the sequences and locations ofprobes and controls. In some embodiments, a machine readable identifierassociated with probe array 140 may indicate the library file directlyor indirectly via one or more identifiers in the array file, to employfor identification of the probes and their positional locations. Theresulting data stored in the .chp file includes degrees ofhybridization, absolute and/or differential (over two or moreexperiments) expression, genotype comparisons, detection ofpolymorphisms and mutations, and other analytical results.

In some alternative embodiments, user 101 may employ differentapplications to process data such as an independent analysisapplication. Embodiments of an analysis application may comprise any ofa variety of known or probe array analysis applications, andparticularly analysis applications specialized for use with embodimentsof probe array 140 designed for genotyping or expression applications.Various embodiments of analysis application may exist such asapplications developed by the probe array manufacturer for specializedembodiments of probe array 140, commercial third party softwareapplications, open source applications, or other applications known inthe art for specific analysis of data from probe arrays 140. Someexamples of known genotyping analysis applications include theAffymetrix GENECHIP® Data Analysis System (GDAS), Affymetrix GENECHIP®Genotyping Analysis Software (GTYPE), Affymetrix GENECHIP® TargetedGenotyping Analysis Software (GTGS), and Affymetrix GENECHIP® SequenceAnalysis Software (GSEQ) applications. Additional examples of genotypinganalysis applications may be found in U.S. application Ser. Nos.10/657,481, 10/986,963, and 11/157,768, each of which is herebyincorporated by reference herein in their entirety for all purposes.Typically, embodiments of analysis applications may be loaded intosystem memory 270 and/or memory storage device 281 through one of inputdevices 240.

Some embodiments of analysis applications include executable code beingstored in system memory 270. Applications 272 may be enabled to export.cel files, .dat files, or other files to an analysis application orenable access to such files on computer 150 by the analysis application.Import and/or export functionality for compatibility with specificsystems or applications may be enabled by one or more integrated modulesas described above with respect to plug-in modules. For example, ananalysis application may be capable of performing specialized analysisof processed intensity data, such as the data in a .cel file. In thepresent example, user 101 may desire to process data associated with aplurality of implementations of probe array 140 and therefore theanalysis application would receive a .cel file associated with eachprobe array for processing. In the present example, applications 272forwards the appropriate files in response to queries or requests fromthe analysis application.

In the same or alternative examples, user 101 and/or the third partydevelopers may employ what are referred to as software development kitsthat enable programmatic access into file formats, or the structure ofapplications 272. Therefore, developers of other software applicationssuch as the described analysis application may integrate with andseamlessly add functionally to or utilize data from applications 272that provides user 101 with a wide range of application and processingcapability. Additional examples of software development kits associatedwith software or data related to probe arrays are described in U.S. Pat.No. 6,954,699, and U.S. patent application Ser. Nos. 10/764,663 and11/215,900, each of which is hereby incorporated by reference herein inits entirety for all purposes.

Additional examples of .cel and .chp files are described with respect tothe Affymetrix GENECHIP® Operating Software or AFFYMETRIX® MicroarraySuite (as described, for example, in U.S. patent application Ser. Nos.10/219,882 and 10/764,663, both of which are hereby incorporated hereinby reference in their entireties for all purposes). For convenience, theterm “file” often is used herein to refer to data generated or used byapplications 272 and executable counterparts of other applications suchas analysis application 380, where the data is written according aformat such as the described .dat, .cel, and .chp formats. Further, thedata files may also be used as input for applications 272 or othersoftware capable of reading the format of the file.

Those of ordinary skill in the related art will appreciate that one ormore operations of applications 272 may be performed by software orfirmware associated with various instruments. For example, scanner 100could include a computer that may include a firmware component thatperforms or controls one or more operations associated with scanner 100.

Yet another example of instrument control and image analysisapplications is described in U.S. patent application Ser. No.11/279,068, titled “System, Method and Computer Product for SimplifiedInstrument Control and File Management”, filed Apr. 7, 2006, which ishereby incorporated by reference herein in its entirety for allpurposes.

Scanner Optics and Detectors 200:

FIG. 3 provides a simplified graphical example of possible embodimentsof optical elements associated with scanner 100, illustrated as scanneroptics and detectors 200.

One embodiment of scanner optics and detectors 200 is shown in FIG. 3.Source 320A may be, for example, a “Luxeon III” light-emitting diodemanufactured by Lumileds Lighting LLC (San Jose Calif., model LXHL-LE3Cor LXHL-LM3C) and having a nominal central wavelength of 505 nm or 530nm. The list price of this LED is fairly inexpensive. Similar LEDs maybe available from other manufacturers such as Cree Inc (Durham N.C.).The actual central wavelength can differ from the nominal centralwavelength by up to 15 nm, and the emission spectrum of the LED has afull width at half maximum of approximately 30 nm. Source 320A emitslight over approximately 2-pi steradians (one hemisphere). A portion ofthe light emitted by source 320A is collimated by lens 323A, which mayby an aspheric lens, for example, having a focal length of 17 mm and adiameter of 25 mm (Newport Corp, Irvine Calif., model KPA031-C).

Source 320B maybe, for example, a “Luxeon” light-emitting diode having anominal central wavelength of 590 nm (Lumileds Lighting LLC, modelLXHL-ML1D). A portion of the light emitted by source 320B is collimatedby lens 323B, which may be also an aspheric lens having a focal lengthof 17 mm and a diameter of 25 mm.

The purpose of source 320A is to excite fluorescence from labeled targetmolecules that are hybridized to probe array 140. Source 320B is usedfor autofocusing, as will be described below. Alternatively, someembodiments of scanner 100 may employ a single embodiment of source 320capable of performing both the excitation and autofocus functions.

Collimated beam 335 generated by lens 323A passes through aperture 325and filter 327. Aperture 325 is an 11 mm×8.5 mm rectangular opening in athin black-anodized aluminum disk. Therefore, immediately after passingthrough aperture 325, beam 335 has a rectangular cross section. Filter327 is a bandpass filter that efficiently transmits light at wavelengthsof 470-550 nm and absorbs or reflects light at other wavelengths, forexample, the filter at Chroma Technology Corp, Rockingham Vt., modelHQ510/80. Similar filters are manufactured by Omega Optical Inc(Brattleboro Vt.) and Semrock Inc (Rochester N.Y.). Alternatively,filter 327 may be a 550-nm shortpass filter that efficiently transmitslight at wavelengths shorter than 550 nm and blocks longer wavelengths.Although source 320A has a nominal central wavelength of 505 nm or 530nm, it emits some light at wavelengths up to 600 nm or even longer. Thepurpose of filter 327 is to prevent this long-wavelength light fromreaching probe array 140 and the detector 390.

Beamsplitter 340 reflects beam 335 and transmits beam 337, in effectcombining the two beams into a single beam, beam 339. Beamsplitter 340is a longpass dichroic beamsplitter that efficiently reflects light at470-550 nm and efficiently transmits light at 570-610 nm. Beamsplitter340 can be a custom dichroic beamsplitter manufactured by a company suchas Chroma Technology Corp or an commercially available color-separationfilter, for example, a filter manufactured by a company such as CheshireOptical (Keene, N.H.). Alternatively, filter 340 can be a spectrallyneutral beamsplitter (for example, a reflective neutral-density filter)that reflects a portion of beam 335 and transmits a portion of beam 337.In FIG. 3, beam 335 is orthogonal to beam 337, and beamsplitter 340operates at an angle of incidence of 45 degrees, but other geometricarrangements are possible.

Beam 339 passes through lens 329, which may be, for example, aplano-convex lens having a focal length of 150 mm (Edmund IndustrialOptics, Barrington, N.J., model 32-975), and is reflected bybeamsplitter 340′, which is a longpass dichroic beamsplitter similar tobeamsplitter 340. Lens 329 focuses beam 339 onto exit pupil 343 of lens350. Beam 339 passes through lens 350, which may be, for example, aNikon CFI Plan Fluor 10× microscope objective having a focal length of20 mm and a numerical aperture of 0.3, and reaches probe array 140.

The purpose of the optical train described above is to illuminate probearray 140 efficiently and uniformly.

For convenience, in the following discussion we use the thin-lensapproximation to describe all of the lenses. The distance from source320A to lens 323A is equal to the focal length of lens 323A, and thedistance from lens 329 to exit pupil 343 is equal to the focal length oflens 329. Therefore an image of source 320A is formed at exit pupil 343.The size of this image is equal to the size of source 320A multiplied bythe focal length of lens 329 and divided by the focal length of lens323A. For maximum illumination efficiency, the focal lengths of lenses323A and 329 should be chosen so that the image of source 320Aapproximately fills or slightly over-fills exit pupil 343.

The distance from exit pupil 343 to lens 350 is equal to the focallength of lens 350 if lens 350 is telecentric, as most microscopeobjectives are. If lens 350 is not telecentric, the distance from exitpupil 343 to lens 350 may be zero.

The distance from aperture 325 to lens 329 is equal to the focal lengthof lens 329, and the distance from lens 350 to probe array 140 is equalto the focal length of lens 350. Therefore an image of aperture 325 isformed at probe array 140. The size of this image is equal to the sizeof aperture 325 multiplied by the focal length of lens 350 and dividedby the focal length of lens 329. Probe array 140 is uniformlyilluminated if aperture 325 is uniformly filled by light from source320A.

The purpose of aperture 325 is to match the illuminated area of probearray 140 to the field of view of detector 390. The dimensions ofaperture 325, and the focal lengths of lenses 350 and 329, should bechosen so that the illuminated area of probe array 140 is equal to orslightly greater than the field of view of the detector 390.Illuminating an unnecessarily large area is undesirable because itincreases the amount of stray light reaching the detector 390 andbecause most fluorescent labels are susceptible to photobleaching.However, aperture 325 can optionally be omitted. In this case, thedistance from lens 323A to lens 329 is equal to the focal length of lens329, and an image of the pupil of lens 323A is formed at probe array140. Probe array 140 is uniformly illuminated if the pupil of lens 323Ais uniformly filled by light from source 320A. This optical arrangementis generally referred to as Kohler illumination.

Similarly, the distance from source 320B to lens 323B is equal to thefocal length of lens 323B, and the distance from lens 323B to lens 329is equal to the focal length of lens 329. An image of source 320B isformed at exit pupil 343, and an image of the pupil of lens 320B isformed at probe array 140.

Labeled target molecules bound to probe array 140 fluoresce whenilluminated by light from source 320A. A portion of the fluorescentlight emitted by the labeled target molecules is collected andcollimated by lens 350. The resulting fluorescent beam 352 istransmitted through beamsplitter 340′ and filter 360 and is focused bylens 370 onto the detector 390. Filter 360 may be a 570-610 nm bandpass,for example the filter at Chroma Technology Corp, Rockingham, Vt., modelHQ590/40, or a 570-nm longpass filter. The purpose of filter 360 is totransmit as much of the desired fluorescence as possible while blockingundesired light. Undesired light consists primarily of light from source320A that is reflected or back-scattered by probe array 140 or by thehousing or support structure of probe array 140. Undesired light canalso consist of fluorescence, phosphorescence, or Raman scattering fromglass, glue, plastic, contaminants on the surface of probe array 140,etc; this undesired light can be blocked by filter 360 if it has anemission spectrum that is sufficiently different from the emissionspectrum of the fluorophore.

The LED, bandpass filter, and dichroic beamsplitter wavelengthsdescribed above are appropriate if the target molecules are labeled withR-phycoerythrin. These wavelengths may need to be altered if otherfluorophores are used. Other fluorophores may include, for example,fluorescein, rhodamine, or cyanine dyes; lanthanide-chelatefluorophores; semiconductor nanocrystals available from Quantum Dot Corp(Hayward, Calif.) or Evident Technologies (Troy, N.Y.); and FRET(fluorescence resonant energy transfer) labels.

For efficient fluorescence excitation, source 320A needs to emit lightat wavelengths that are strongly absorbed by the fluorophore, and filter327 needs to have high transmittance at these wavelengths. Filter 360needs to have high transmittance at the wavelengths at which thefluorophore emits light. The passbands of filter 327 and filter 360should not overlap.

Light Source and Electronics

In one embodiment, each LED light source is driven in constant-currentmode by a Texas Instruments model PT6214 regulator. The PT6214 isprimarily intended as a voltage source but can be configured as acurrent source by means of a current-sensing feedback resistor.Alternatively, a variety of other LED drivers are commerciallyavailable. When the current is set to 0.9 A (which is 90 percent of themaximum recommended current for the Luxeon III LED), the heat producedby the LED is approximately 3 W. Each LED is mounted on a finned heatsink and optionally cooled by a small fan. Each LED can be turned on andoff by means of a digital (TTL) signal (buffered by an SN7407 or similaropen-collector buffer) applied to the “Inhibit” pin of the PT6214. TheTTL signals can be supplied by a digital input-output board installed incomputer 150, or by auxiliary digital outputs of the motion controller,or by auxiliary digital outputs of the detector 390. LED efficiencydecreases as temperature increases. Optionally the LEDs can bethermoelectrically cooled or liquid-cooled, but these methods add to thecost and complexity of the instrument.

Electronically the instrument is very simple. The instrument may becontrolled by a standard desktop or laptop computer, or optionally by anembedded computer in the scanner system 100. The computer communicateswith the camera and the motion controller by means of, for example, anIEEE-1394 (FireWire) interface and an RS-232 or RS-485 interfacerespectively. No frame grabbers or other data acquisition boards arerequired. The only custom circuit board required may be the very simplecircuit board used to control the LEDs. Power to the camera is suppliedover the IEEE-1394 cable. Power to the motion controller and the LEDs issupplied by a 12 V, 6.5 A switching power supply, for example, the powersupply commercially available at Digi-Key Corp, Thief River Falls Minn.,model SPN75-12S or similar. Software to control the instrument iswritten in Microsoft Visual Basic, Visual C++, or another suitablelanguage.

Examples of Detectors and Imaging Optics

In one embodiment, the detector 390 may be a scientific-grade digitalcamera (for example, Hamamatsu Corp, Bridgewater N.J., model C8484-05G)containing a CCD (charge-coupled device) sensor. The sensor contains arectangular array of 1.37 million (1344×1024) light-sensitive pixels.Each pixel is 6.45 microns square. The overall size of thelight-sensitive area of the sensor is therefore 6.6048 mm×8.6688 mm.Detection quantum efficiency at 590 nm exceeds 60 percent. The camerahas 12-bit digital output. The Hamamatusu C8484-05G model is an uncooledcamera, and dark current is approximately 1 electron/pixel/second whenambient temperature is near 250 C. Dark current does not contributesignificantly to camera noise for integrations as long as 10 seconds. Athermoelectrically cooled version (C8484-03G) is available but moreexpensive. Other similar cameras are available from other manufacturerssuch as Photometrics (Tucson, Ariz.), Cooke Corp (Romulus, Mich.), andSensovation (Belmont, Calif.). Most of these cameras contain a Sonymodel ICX285AL CCD sensor.

In another embodiment, Lens 370 is constructed from two achromaticcemented doublets (for example, Newport Corp, Irvine, Calif., modelPAC067), each having a focal length of 250 mm and a diameter of 25.4 mm.Similar lenses are available from several other suppliers. Thiscombination of lenses has a focal length of 126.28 mm at 590 nm when theair space between the 2 achromats is 1 mm. The focal length is dependenton the air space. For example, the focal length is 129 mm when the airspace is 11.42 mm. Optical design software, for example, such as Zemax(Zemax Development Corp, San Diego, Calif.) or Oslo (Lambda ResearchCorp, Littleton, Mass.) can be used to calculate the optical propertiesof the lens combination.

In FIG. 3, an image of a probe array 140 is formed at the detector 390.A 6.45 micron pixel size camera, a 20 mm focal length for the 350 lens,and a 129 mm focal length for 370 lens are provided as discussed aboveaccording to one embodiment. The effective pixel size at the probe array140 is equal to the pixel size of the detector 390 multiplied by thefocal length of the lens 350 and divided by the focal length of lens370. Therefore, in this embodiment, the effective pixel size would be1.00 micron. In addition, since the sensor of the detector contains arectangular array of 1.37 million (1344×1024) light-sensitive pixels,the field of view of the detector 390 would be 1.344 mm×1.024 mm. Thesize of the area illuminated by source 320A is the size of the aperture325, for example, an 11 mm×8.5 mm. In this example, the size of the areailluminated by source 320A (11 mm×8.5 mm) is slightly larger than thefield of view of the detector 390 (1.344 mm×1.024 mm). In oneembodiment, the focal lengths 370 and 350 may be optimized as discussedbelow to produce an illuminated area of probe array 140 that is closerin size to the field of view of the detector 390.

Different systems are described below by utilizing four microscopeobjectives that are described in the table below. In this table, depthof field and Airy disk diameter are shown for a wavelength of 590 nm.“Cover glass thickness” in this table means the cover glass thicknessthat the objective is designed for (which might not be the cover glassthickness at which it is actually used).

Manufacturer Nikon Nikon Model CFI Plan CFI Plan Fluor 10x Apochromat 4xFocal length (mm) 50 20 Numerical aperture 0.2 0.3 Field of view (mm,diameter) 6.25 2.5 Exit pupil diameter (mm) 20 12 Depth of focus(microns) +/−7.38 +/−3.28 Airy disk diameter (microns) 3.60 2.40 Coverglass thickness (mm) 0 0.17 Manufacturer Olympus Nikon Model UPLSAPO 10xCFI Plan Fluor ELWD 60x C Focal length (mm) 18 3.333 Numerical aperture0.4 0.7 Field of view (mm, diameter) 2.65 0.416 Exit pupil diameter (mm)14.4 4.666 Depth of focus (microns) +/−1.84 +/−0.60 Airy disk diameter(microns) 1.80 1.03 Cover glass thickness (mm) 0.17 0.5-1.5

Optical terms such as “Airy disk diameter,” “numerical aperture,” etc.are well-known to those of ordinary skill in the art and are describedin references such as Modern Optical Engineering (W. J. Smith,McGraw-Hill, 2000) and Optical System Design (R. E. Fischer and B.Tadic-Galeb, McGraw-Hill, 2000).

Airy disk diameter is inversely proportional to numerical aperture;therefore, spatial resolution increases as numerical aperture increases.In addition, fluorescence collection efficiency is proportional to thesquare of the numerical aperture. For these reasons, a high numericalaperture is desirable. On the other hand, the diameter of the field ofview of a microscope objective is inversely proportional to the nominalmagnification (4×, 10×, 60×, etc); and as shown in the table, numericalaperture is low when nominal magnification is low. Furthermore, thedepth of focus is inversely proportional to the square of the numericalaperture, meaning that tight autofocus tolerances are required if a highnumerical aperture objective is used. For these reasons, the choice ofmicroscope objective depends on the application.

In one embodiment, a Nikon CFI Plan Fluor 10× objective and an effectivepixel size of 1 micron are provided, as described above. Thecenter-to-center distance between the features on probe array 140 isbetween approximately 5 and 10 microns.

In another embodiment, an Olympus UPLSAPO 10× objective, an effectivepixel size of 1 micron, and a focal length 370 of 116.1 mm are provided.The Olympus objective has a higher numerical aperture than the Nikon CFIPlan Fluor 10×, enabling more fluorescent photons to be collected perunit time.

In an alternate embodiment, a center-to-center distance of 1 micronbetween features on probe array 140, a Nikon CFI Plan Fluor ELWD 60× Clens 350, and a commercially available achromatic cemented doublethaving a focal length of 120 mm lens 370 are provided. This combinationof lenses gives an effective pixel size of 0.179 microns (6.45 micronsmultiplied by 3.333 mm and divided by 120 mm).

As another alternative, lens 350 is a Nikon CFI Plan Apochromat 4×. Lens370 has a focal length of 117 mm and is made from three commerciallyavailable achromats (two with focal lengths of 300 mm and one with afocal length of 400 mm). Effective pixel size is 2.75 microns (6.45microns multiplied by 50 mm and divided by 117 mm). The field of view ofthe detector 390 is 2.8 mm×3.7 mm. This configuration can be useful ifthe center-to-center distance between features on probe array 140 islarger than approximately 14 microns.

Correction of Spherical Aberration

Most standard microscope objectives exhibit minimal spherical aberrationwhen the object being scanned is on a cover glass with a thickness of,for example, 170 microns which is located between the objective and thefocal plane. Objectives intended for use with thicker cover glassesexist, but they are not necessarily available with the desired focallength and numerical aperture. Undesired spherical aberrations can becreated when the object being scanned is thicker, for example, anAffymetrix array cartridge (See, U.S. Pat. Nos. 5,445,934, 5,744,305,5,945,334, 6,140,044, 6,261,776, 6,291,183, 6,346,413, 6,399,365,6,420,169, 6,551,817, 6,610,482, 6,733,977, and 6,955,915 for examplesof array cartridges), which is a probe array with a substrate thicknessof approximately 700 microns, assembled in a housing. Furthermore, thespherical aberrations can be larger when the probe array 140 is immersedin a scan tray, for example, an Affymetrix array plate (See, forexample, U.S. patent application Ser. No. 11/347,654 for examples ofarray plate and scan plates), which is mounted on a peg that is immersedin a scan tray during scanning. The increased spherical aberration iscaused by the thick window at the bottom of the scan tray and thepresence of an aqueous liquid layer between the window and the probearray. Spherical aberration has both a magnitude and a sign andtherefore, may be corrected in at least 3 ways according to anembodiment of the invention.

The first method comprises using a custom tube lens. In this method, thespherical aberration produced in the custom tube lens may be utilized bycancelling the spherical aberration caused by, for example, the scantray window and the liquid layer.

The second method comprises using an infinite-conjugate microscopeobjective at a finite conjugate ratio and is described below. Aninfinite-conjugate objective at a finite conjugate ratio causesspherical aberration. Therefore, a finite conjugate ratio may be chosenappropriately such that the resulting spherical aberration may cancelthe spherical aberration caused by the peg plate window and liquid. Thethird method comprises using a combination of method 1 and method 2described above. Further details of these methods are described below.

In one embodiment, a microscope objective is optimized to create anamount of spherical aberration to cancel the spherical aberrationcreated from using a thick cover glass. In an alternative embodiment, astandard microscope object may be used with a lens 370 that can bedesigned to reduce or eliminate the spherical aberration caused by thethick window. In a further embodiment, the lens 370 is well-correctedfor off-axis aberrations such as coma, field curvature, lateral color,astigmatism, and distortion.

The microscope objectives discussed above are infinite-conjugateobjectives, meaning that they are designed for use at infinite conjugateratio. Spherical aberration can result when an infinite-conjugateobjective that is designed for a particular cover glass thickness isused with that cover glass thickness but at a finite conjugate ratio.However, the spherical aberration caused by the cover glass can becancelled by using the objective at a finite conjugate ratio when aninfinite-conjugate objective is used with a cover glass thickness thatit was not designed for. See S. Stallinga, “Finite conjugate sphericalaberration compensation in high numerical-aperture optical discreadout,” Applied Optics 44, 7307-7312 (2005), and references containedtherein. The distance from the second principal point of lens 370 to theCCD sensor in the camera 390 is equal to the focal length of lens 370when objective 350 is used at infinite conjugate ratio. The distancefrom the second principal point of lens 370 to the CCD sensor in thecamera 390 can be several millimeters less than the focal length of lens370 when objective 350 is used at a finite conjugate ratio.

In one embodiment, lens 370 includes one or more custom optical elementsto correct off-axis aberration. Examples of lenses are shown in thetable below. The 370 lens uses two commercially available cementeddoublets and one custom cemented doublet according to an embodiment. Ina further embodiment, the lens 370 is used with an Olympus UPLSAPO 10×objective.

Radius of curvature Thickness (mm) (mm) Material Notes 205.72 4.0 SF5Edmund Optics 32923 70.73 8.5 BK7 −98.66 1.0 air 667.68 4.0 SF5 EdmundOptics 45270 224.08 6.0 BK7 −305.31 67.0 air 16.916 6.0 S-TIL6 customlens −40.831 3.0 S-BAM4 14.27 25.0 air image plane

In one embodiment, the instrument is used to obtain images of a DNAarray having a synthesis area of, for example, 5.9 mm×5.9 mm. Becausethe synthesis area is much larger than the field of view of the detector390, the array is divided into, for example, 49 sub-arrays, each havingdimensions of approximately 850 microns×850 microns. Alternatively, thearray is divided into 35 sub-arrays, each having dimensions ofapproximately 850 microns×1180 microns. Probe array 140 is positioned sothat the first sub-array is centered in the field of view of thedetector 390, focus is adjusted (as explained below), and an image ofthe first sub-array is obtained. This image is displayed on the computerscreen as a gray-scale or false-color image and written to disk in, forexample, Affymetrix “dat” format, “tif” format, or any other desiredformat. Probe array 140 is then moved so that the second sub-array iscentered in the field of view of the detector 390. The focus is adjustedand an image of the second sub-array is obtained. These steps arerepeated until all the sub-arrays are imaged. In an alternateembodiment, 2 images of each sub-array are taken: a short exposure (forexample, a 0.2-second integration) to capture data from bright features,and a long exposure (for example, a 2-second integration) to improve thesignal-to-noise ratio for dim features.

FIG. 4A shows an example of an image of a sub-array 400, specifically, afluorescence image of a central sub-array. The nominal size of eachfeature is 8 microns×8 microns. (The center-to-center feature spacing is8 microns×8 microns. The actual size of each feature is 6 microns×6microns. There are 2-micron blank streets between features.)

In one embodiment, an inexpensive translation stage provides sufficientaccuracy because each sub-array is about 200 microns smaller than thefield of view of the detector 390. Thus, the centration of eachsub-array in the field of view can be approximated.

In another embodiment, dark-field and bright-field correction areperformed on the images. Dark-field correction is particularly desirablewhen using an uncooled camera for long integrations. “Hot pixels,” whichhave much higher dark current than the other pixels in the detector,show up as bright spots in the image if dark-field correction is notperformed. Bright-field correction is particularly useful if source 320Ailluminates the field of view of the detector 390 with non-uniform powerdensity. Both dark-field and bright-field correction are well known tothose of ordinary skill in the art.

According to one embodiment, a set up method for imaging a probe arrayis provided. A surface on the probe array which includes a plurality offiducials is provided. The fiducials are focused and measured. Themeasurements describes a relative position of each fiducial. Themeasurement data are transmitted to a computer that includes a surfacefitting algorithm. A surface profile is calculated on the computer thatemploys the surface fitting algorithm and the transmitted measurementdata. One or more surface non-flatness parameters are adjusted based onthe calculations. The surface non-flatness parameters are parametersthat can be changed to improve the image flatness of the surface.Examples of surface non-flatness parameters include array tilt, stagemovement effect and optical parameters, such as the choice of lens. Theflatness of the surface can also be improved by adjusting a focal plane,for example, by moving a lens or the camera. The steps described aboveare repeated until the relative distance of each fiducial on the probearray are positionally optimized for setting up the probe array to beimaged.

In alternate embodiments, the method may include a number of fiducials,for example, at least 4, at least 5 and at least 9 fiducials. Thesurface fitting algorithm may include a least square, sub-plane surfacefit, and B spline surface fit.

In another embodiment, the set up method includes a tilt stage which isdescribed later in the application. The focusing includes tilting thetilt stage so that the array surface is made parallel to a focal planeof a microscope objective.

Translation/Tilt Stage

Depth of focus according to the standard textbook formula used in thefield is lambda /NA², where lambda=wavelength and NA=numerical aperture.There can be significant variations in focus across a sub-array if thedepth of focus of lens 350 (for example, see FIG. 3) is short. Forexample, at 590 nm (the central wavelength of a typical phycoerythrinemission filter), where a probe array 140 is mounted on a peg that isimmersed in a 4-peg or 96-peg scan tray, the depth of focus of lens 350can be less than 4 microns. To improve the focus across a sub-array, aprobe array 140 can be mounted on a 2-axis tilt stage such that thepitch, yaw and roll can be adjusted during the autofocus process. Duringthe autofocus process, the tilt stage can be tilted so that the pegsurface is made parallel to the focal plane of the microscope objectiveaccording to an embodiment of the present invention. If the peg surfaceis tilted with respect to the focal plane of the microscope objectiveand a perfect focus in the middle of the CCD camera's field of view isachieved, the maximum tolerable tilt is equal to the depth of focusdivided by the field diagonal. Assumptions that a diffraction-limitedimage quality across the entire field is desired and the optical systemhas no aberrations except for defocus are made. Tolerable tilt can becontrolled by having the scanner comprise a 2-axis tilt stage on whichthe peg or peg plate is mounted according to an embodiment of theinvention.

In another non-limiting embodiment, probe array 140 can be mounted on a3-axis translation stage (for example, Deltron Precision Inc, BethelConn., model LS2-1-A05-XYZ-E-NPN-1). Other suitable translation stagesare available from companies such as THK America Inc., Schaumburg, Ill.and IKO International Inc, Torrance, Calif. The X and Y axes oftranslation are parallel to the plane of probe array 140 and arerequired if the synthesis area of probe array 140 is larger than thefield of view of the detector 390. The Z axis is parallel to the opticalaxis of lens 350 (perpendicular to the plane of probe array 140) and isused for focus adjustment (for example, see FIG. 3). Each axis may bedriven by a stepping motor, for example, a size 14 stepping motor havinga step size of 0.9 degrees (Lin Engineering, Santa Clara Calif., model3509V-03-01), though other motors may be used. The motors are controlledby a 3-axis motion controller (for example, SimpleStep LLC, Newton N.J.,model SSXYZMicro77). Leadscrew pitch may be 0.05 inches, for example,and the motors may be driven in microstepping mode with 8 microsteps perfull step (3,200 microsteps per revolution). Therefore the size of eachmicrostep is nominally 0.396875 microns. The degrees of freedom are 2axes of tilt plus one axis of translation (the translation axis can beused for focus adjustment—alternatively, the instrument's main Z stagecan be used for focus adjustment). The tilt stage can be, for example, akinematic tilt stage with 2 stepping-motor-driven actuators (not 3), atilt stage with piezoelectric actuators instead of stepping motors, aflexure tilt stage, a gimbal stage, a hexapod, or 2 orthogonalgoniometers. Examples of motors to drive the tilt stage are, forexample, conventional stepping motors, miniature stepping motors(MicroMo Electronics Inc, Clearwater Fla.), servo motors, linear motorsor piezoelectric actuators. The translation stages can optionallyinclude linear or rotary encoders. Alternatively, probe array 140 can bemounted on a two-axis (XY) stage and lens 350 can be mounted on asingle-axis (Z) stage. The Z axis can be vertical, horizontal, or atsome other angle.

The 3-axis translation stage might not be necessary. The Z axis (and theautofocus process) can be omitted if mechanical tolerances in packagingand mounting probe array 140 are sufficiently tight. The X and Y axescan be omitted if probe array 140 is smaller than the field of view ofthe detector 390.

Filter Wheel/Filter Slider

According to an embodiment of the present invention, an example of afilter slider 900 is provided as shown in FIG. 8. The target moleculescan be labeled with light-scattering particles (for example, gold orsilver nanoparticles with diameters in the range of approximately 1 to100 nanometers) or with phosphorescent labels instead of fluorescentlabels. Filter 360 can be replaced by two or more filters (havingdifferent transmission spectra) mounted on a manual or motorized filterwheel or filter slider. The instrument can then be used to sequentiallyobtain two-color or multi-color, for example, 4 color (or 1-, 2-, or3-color) fluorescence images of the array to which has been hybridizedlabeled sample nucleic acid, which can be useful if the target moleculeshybridized to probe array 140 are labeled with two or more differentfluorophores. For example, if target molecules are labeled with fourdifferent semiconductor nanocrystal labels having peak emissionwavelengths of 565 nm, 605 nm, 655 nm, and 705 nm, suitable emissionfilters include Chroma models HQ565/40, HQ605/40, HQ655/40, and HQ705/40respectively. In a further embodiment, biotin-streptavidin-phycoerythrinand fluorescein-antifluorescein-allophycocyanin orbiotin-streptavidin-allophycocyanin andfluorescein-antifluorescein-phycoerythrin are used. The instrument canbe used to simultaneously obtain two-color or multi-color images if itcontains two or more cameras. For each color there can be a filter setcontaining an excitation filter 901, a beamsplitter 902, and an emissionfilter 903. Either the excitation filter 901 or the emission filter 903or both filters can be omitted with a filter set. The beamsplitter 902can be either a dichroic beamsplitter or a neutral-density filter. The 5(or fewer) filter sets are mounted in a filter block 904 that is mountedon a linear slide 905. The linear slide 905, for example, arecirculating ball slide manufactured by THK or IKO, is driven by alinear actuator 906 manufactured by, for example, HaydonKerk MotionSolutions, Waterbury, Conn. The linear slide is connected to the linearactuator by a slide bracket 907. The linear actuator 906 can include astepping motor, a leadscrew, and a leadscrew nut. The linear actuator906 is coupled to the linear slide 905 using a slider blade 908, forexample, a thin piece of steel shim stock bent into an L shape. Thiscouple is sufficiently flexible so that the filter slider functionsproperly even if the linear actuator is angularly or laterallymisaligned relative to the linear slide. An EOT flag 911 can beinstalled and a nut bracket 912 can be used to couple the slider bade tothe actuator. The support arm 910 can be mounted to the chassis of theinstrument. An amplified photo microsensor 913 and a deep groove ballbearing 914 is attached to the support arm.

Probe array 140 does not need to be a DNA array. It could be a peptidearray or some other type of array. The instrument described above canscan an array on a peg, array on a peg strip, array on a plate, etc.(See U.S. patent application Ser. No. 11/243,621 which is herebyincorporated by reference herein in its entirely for all purposes).

An additional example of a scanner system with a similar opticalarchitecture is described in U.S. patent application Ser. No.11/379,641, titled “Methods and Devices for Reading Microarray”, filedApr. 22, 2005 which is hereby incorporated by reference herein in itsentirety for all purposes.

In an additional embodiment, disclosed is a method of manufacturing afilter slider for reading a biological array. A linear slide and aplurality of filter sets are provided (See FIG. 8). The filter sets aremounted in a fixture that is mounted on a linear slide. A linearactuator is also provided and coupled to the linear slide such that thefiler slider functions properly even if the linear actuator ismisaligned relative to the linear slide. The linear actuator comprises amotor. In an alternate embodiment, the motor is a stepping motor and ablade slider, such as a steel shim stock couples the linear actuatorwith the filter slider.

Autofocusing

The plane of probe array 140 is usually not exactly parallel to the XYplane of the translation stages because of mechanical tolerances inpackaging probe array 140 and mounting probe array 140 on theinstrument. Therefore, optimum focus can be different for eachsub-array. Each corner sub-array can contain at least one reflectivefeature, for example, a chrome square or L such as reflective feature405. In one embodiment, a corner sub-array is illuminated by the 590-nmLED, and images are taken as focus is adjusted in 1-micron to 10-micronsteps. Sharpness is calculated for each image. Sharpness at other Zpositions can be calculated by quadratic interpolation (parabolafitting). The sub-array is in best focus when the calculated sharpnessis a maximum. This process is performed for each of the cornersub-arrays before any of the fluorescence images are taken. Optimumfocus for the other sub-arrays may be interpolated.

According to a embodiment, a method to image a probe array is provided.A plurality of fiducials on the surface of the probe array is used toimprove the image flatness of the surface image. A plurality of imagesis taken with a camera at a plurality of different z positions. Thesharpness at each z position is determined by using one or more imagesoftware program. A best z position is chosen by comparing the images ofthe various z positions and choosing the sharpest image. The above stepsare repeated until the best z position of each fiducial on the probearray are determined. The data are transmitted to a computer, whereinthe computer includes a surface fitting algorithm. A surface fit profileis calculated on the computer employing the surface fitting algorithmand the transmitted measurement data. Based on the calculations of thesurface fit profile, one or more surface non-flatness parameters can beadjusted to improve the image flatness of the surface image of the probearray.

In alternate embodiments, the imaging method may include a number offiducials, for example, at least 4, at least 5 and at least 9 fiducials.The surface fitting algorithm may include a least square, sub-planesurface fit, and B spline surface fit.

In another embodiment, the imaging method includes the array on a tiltstage which is discussed later in the application. The focusing includestilting the tilt stage so that the array surface is made parallel to afocal plane of a microscope objective.

In a further embodiment, the surface non-flatness parameters include anarray tilt, stage movement effect and optical parameters. In anotherembodiment, the surface non-flatness parameter, a focal plane isadjusted by moving a lens.

These methods may be applicable in many different systems, globally,across the field of microarray analysis. Having described variousembodiments and implementations, it should be apparent to those skilledin the relevant art that the foregoing embodiments are merelyillustrative and not limiting, having only been presented by way ofexample. Many other schemes for distributing functions among the variousfunctional elements of the illustrated embodiment are possible. Thefunctions of any element may be carried out in various ways inalternative embodiments.

Also, the functions of several elements may, in alternative embodiments,be carried out by fewer, or a single, element. Similarly, in someembodiments, any functional element may perform fewer, or different,operations than those described with respect to the illustratedembodiment. Also, functional elements showed as distinct for purposes ofillustration may be incorporated within other functional elements in aparticular implementation. Also, the sequencing of functions or portionsof functions generally may be altered. Certain functional elements,files, data structures, and so on may be described in the illustratedembodiments as located in system memory of a particular computer. Inother embodiments, however, they may be located on, or distributedacross, computer systems or other platforms that are co-located and/orremote from each other. For example, any one or more of data files ordata structures described as co-located on and “local” to a server orother computer may be located in a computer system or systems remotefrom the server. In addition, it will be understood by those skilled inthe relevant art that control and data flows between and amongfunctional elements and various data structures may vary in many waysfrom the control and data flows described above or in documentsincorporated by reference herein. More particularly, intermediaryfunctional elements may direct control or data flows, and the functionsof various elements may be combined, divided, or otherwise rearranged toallow parallel processing or for other reasons. Also, intermediate datastructures or files may be used and various described data structures orfiles may be combined or otherwise arranged. Numerous other embodiments,and modifications thereof, are contemplated as falling within the scopeof the present invention as defined by appended claims and equivalentsthereto.

In another non-limiting embodiment, the reflected-light images can alsobe used to adjust the position of probe array 140 in the X and Ydirections to ensure that each sub-array is centered in the field ofview of the detector 390, because the positions of the chrome featuresrelative to the fluorescent features can be known, for example, thechrome features shown in FIGS. 4A and 4B. The chrome features can be invarious substrates which are understood for one skilled in the art invarious applications, for example, biological, biotechnology, medicaldiagnostics, chemical reactions, and the like. FIGS. 4A and 4B areimages of corner sub-arrays 400 taken with both 530-nm excitation (forfluorescence imaging) and 590-nm excitation (for reflected-lightimaging), respectively. The small square features are fluorescentlylabeled. The large L-shaped feature is a chrome mark, illustrated asreflective feature 405 that is used for autofocusing. The surfaceprofile of an array is a larger factor as one goes to smaller featuresizes. Factors that cause a non-flat surface include, for example, atilt (how parallel the array surface is to the scanner focus plane),stage movement effect (flatness and thread), array surface roughness,and optical parameters. Many other methods and arrangements of autofocusfeatures are possible as described in the following non-limitingexamples. In these examples, a fiducial is located at the center of eachsubarray.

According to one embodiment, autofocus features or fiduciaries arelocated near the four corners of probe array 140 in the 4-pointanalysis. The number of points and locations of the fiducials (510) onan array 500 that are measured for the 4-point analysis are indicated inFIG. 5A. The shape of each plane 511 that is being analyzed is alsoindicated in FIG. 5A. FIG. 5B shows a scanned image of the results fromthe 4 points array surface analysis. The factors that cause a non-flatsurface, for example, a focal plane, can be adjusted. FIG. 5C shows acomparison of a characterization of the array surface between the“calculated” surface and the actual surface. The X axis 515 displays thelocation on the array and the Y axis 516 displays the relative height tothe lowest corner. According to an embodiment, additional autofocusfeatures or fiducials are used to calculate the array surface profile.

FIGS. 6A, 6B, and 6C illustrate a 5-point auto-focusing method accordingto another embodiment of the present invention. The number of points andlocations of the fiducials (510) on an array 500 that are measured forthe 5-point analysis are indicated in FIG. 6A. The shape of each plane511 that is being analyzed is also indicated in FIG. 6A. FIG. 6B shows ascanned image of the results from the 5 points array surface analysis.Auto focusing is performed to the four corners and a center mark. Thetilt is adjusted and small compensations of stage movement are made.FIG. 6C shows the comparison of the characterization of the arraysurface between the “calculated” surface of the 5 point auto focusingmethod and the actual surface.

FIGS. 7A, 7B, 7C, 7D and 7E illustrate a 9-point auto-focusing methodaccording to a further embodiment of the invention. The number of pointsand locations of the fiducials (510) on an array 500 that are measuredfor the 9-point analysis are indicated in FIG. 7A. The shape of eachplane 511 that is being analyzed is also indicated in FIG. 7A. FIG. 7Bshows a scanned image of the results from the 9 points analysis. Byperforming the 9 point analysis with a surface fitting algorithm, thetilt can be adjusted and compensations for stage movement and for thearray surface roughness can be made. Various surface fitting algorithmsare known in the art, for example, least square, sub-plane surface fit,and the B spline surface fit. FIGS. 7C, 7D, and 7E show the comparisonsof the characterization of the array surface between the “calculated”and the actual surface by using these surface fitting algorithms. FIG.7C shows the results from using the least square algorithm, where thebest fit plane is determined by using the nine measurements with theassumption that the array surface is linear. The sub-plane surface fitalgorithm includes dividing the array surface into small sub-planes andusing multiple planes to describe the array surface. FIG. 7D shows theresults from using the sub-plane surface fit algorithm. The assumptionthat the array surface is smooth and curved is made when using the Bspline surface fit algorithm. The results from using the B splinesurface fit algorithm are shown in FIG. 7E.

Many other arrangements of autofocus features are possible as describedin the following non-limiting examples. For example, autofocus featurescan be located near three corners of probe array 140, or in threenon-collinear locations that are not corners. Alternatively, a singleautofocus feature may be located near the middle of probe array 140, andthe other autofocus features may be absent. As another alternative,every one of the sub-arrays might contain one or several autofocusfeatures (for example, 1, 3, 5, 9, 12, 15, etc). The number of autofocusfeatures and locations will depend on factors such a shape of a probearray, number of subarrays, feature size, throughput requirements, stageaccuracy, depth of focus of the optics, etc.

In addition to several different arrangements of autofocus features,there are also several other autofocus methods that are possible. Forexample, source 320B can be omitted, and source 320A can be used toobtain images of the reflective features for purposes of finding focus.In this case, filter 360 is mounted on a motorized slider or filterwheel and is removed from the optical path during the autofocus process(because filter 360 has no transmission at the emission wavelengths ofsource 320A). Alternatively, the reflective features can be omitted, andautofocus can be performed by taking a series of fluorescence images.This method is undesirable if the fluorophores are susceptible tophotobleaching. As another alternative, the features used forautofocusing can be polyimide rather than chrome.

Additional examples of reflective elements and methods such as theparabola fit employed for auto-focus are described in U.S. patentapplication Ser. No. 10/389,194, titled “System, Method and Product forScanning of Biological Materials”, filed Mar. 14, 2003; and U.S. patentapplication Ser. No. 10/769,575, titled “System and Method forCalibration and Focusing a Scanner Instrument Using Elements Associatedwith a Biological Probe Array”, filed Jan. 29, 2004; both of which arehereby incorporated by reference herein in its entirety for allpurposes.

In some embodiments, the autofocus methods described in U.S. Pat. Nos.5,578,832 and 5,631,734, both of which are hereby incorporated byreference herein it their entireties for all purposes, may be employedinstead of the autofocus methods described above.

According to an embodiment of the present invention, a method toincrease the speed of autofocusing is provided. A CCD readout speed is,for example, 20 million pixels per second. According to an embodiment, amethod to speed up the autofocus is provided. Instead of reading out,for example, all 2048×2048 pixels from the CCD, a region of interest canbe defined on the CCD and only the pixels from the region of interestcan then be read. In an alternative embodiment of the present invention,the method comprises binning pixels in groups of for example, 2×2, andreading out the binned pixels instead of the individual pixels.

Many variations of the instrument described above are possible. Some ofthese variations are listed below. The instrument can hold several probearrays and scan them sequentially. The instrument can scan a well plate,for example, a 96-well plate, a 384-well plate, etc., if the translationstages have sufficient travel. The positions of source 320A and source320B can be switched. In this case, beamsplitter 340 can be a shortpassdichroic beamsplitter instead of a longpass dichroic beamsplitter. Oneor both LEDs can be replaced by sources such as a plurality of LED (i.e.greater than two LEDs), a white light LED, a solid state light source(Lumen Corp, San Diego, Calif.), an arc lamp, a flash lamp, ametal-halide lamp, or a laser.

Abbe illumination can be used instead of Kohler illumination. If Abbeillumination is used, it might be desirable to homogenize the light fromsource 320A by means of a rectangular light pipe or, light tunnel, orrandomizing fiber-optic bundle, with the exit face of the homogenizerbeing imaged onto probe array 140.

If lens 350 has a sufficiently long working distance, light from source320A can bypass lens 350 and strike probe array 140 at an angle ofincidence of approximately 45 degrees. In this case, it might bedesirable to use several LEDs surrounding lens 350 for fluorescenceexcitation instead of a single LED.

A mirror can be used to introduce a 90-degree bend in the optical pathbetween beamsplitter 340′ and exit pupil 343, or between beamsplitter340′ and filter 360, or between lens 370 and the detector 390. This90-degree bend might make the optical system more compact.

The focal lengths and focal-length ratios of lenses 323A, 323B, and 329can be changed. Lens 370 can be a commercially available camera lens ora custom multi-element lens. Lens 350 can be a single-element ormulti-element lens that is not a microscope objective. Lens 350 can be afinite-conjugate rather than an infinite-conjugate objective; in thiscase, lens 370 can be omitted.

Cameras having a larger or smaller number of pixels and larger orsmaller pixel sizes can be used. Cameras with 4.19 millionlight-sensitive pixels (2048×2048) are available from severalmanufacturers including Apogee Instruments Inc (Roseville Calif., modelU4000) and Roper Scientific Inc (Tucson Ariz., model K4); the pixel sizefor these cameras is 7.4 microns×7.4 microns. Cameras with 11 millionlight-sensitive pixels are available also. The camera can have 8, 10,12, 14, or 16-bit digital output and can use a USB (universal serialbus), IEEE-1394 (FireWire), or PCI interface. Alternatively, the cameracan have analog output that is digitized by a frame grabber. The cameracan contain a CMOS sensor rather than a CCD sensor. In some cases, avery inexpensive consumer-grade camera might be usable.

C. Applications Using Nucleic Acid Arrays

A variety of applications using nucleic acid arrays are described inU.S. Pat. No. 7,005,259, which is hereby incorporated herein byreference in its entirety for all purposes.

The methods and compositions described herein may be used in a range ofapplications including biomedical and genetic research as well asclinical diagnostics. Arrays of polymers such as nucleic acids may bescreened for specific binding to a target, such as a complementarynucleotide, for example, in screening studies for determination ofbinding affinity and in diagnostic assays. In one embodiment, sequencingof polynucleotides can be conducted, as disclosed in U.S. Pat. No.5,547,839. The nucleic acid arrays may be used in many otherapplications including detection of genetic diseases such as cysticfibrosis, diabetes, and acquired diseases such as cancer, as disclosedin U.S. patent application Ser. No. 08/143,312 (abandoned). Geneticmutations may be detected by sequencing by hydridization. In oneembodiment, genetic markers may be sequenced and mapped using Type-IIsrestriction endonucleases as disclosed in U.S. Pat. No. 5,710,000.

Other applications include chip based genotyping, species identificationand phenotypic characterization, as described in U.S. Pat. No.6,228,575, filed Feb. 7, 1997, and U.S. application Ser. No. 08/629,031(abandoned), filed Apr. 8, 1996. Still other applications are describedin U.S. Pat. No. 5,800,992.

Gene expression may be monitored by hybridization of large numbers ofmRNAs in parallel using high density arrays of nucleic acids in cells,such as in microorganisms such as yeast, as described in Lockhart etal., Nature Biotechnology, 14:1675 1680 (1996). Bacterial transcriptimaging by hybridization of total RNA to nucleic acid arrays may beconducted as described in Saizieu et al., Nature Biotechnology, 16:45 48(1998). Accessing genetic information using high density DNA arrays isfurther described in Chee, Science 274:610 614 (1996).

Still other methods for screening target molecules for specific bindingto arrays of polymers, such as nucleic acids, immobilized on a solidsubstrate, are disclosed, for example, in U.S. Pat. No. 5,510,270.

Devices for concurrently processing multiple biological chip assays areuseful for each of the applications described above (See, for example,U.S. Pat. No. 5,545,531). Methods and systems for detecting a labeledmarker on a sample on a solid support, wherein the labeled materialemits radiation at a wavelength that is different from the excitationwavelength, which radiation is collected by collection optics and imagedonto a detector which generates an image of the sample, are disclosedin, for example, U.S. Pat. No. 5,578,832. These methods permit a highlysensitive and resolved image to be obtained at high speed. Methods andapparatus for detection of fluorescently labeled materials are furtherdescribed in U.S. Pat. Nos. 5,631,734 and 5,324,633.

Typically, in carrying out these methods, the housed substrate ismounted on a hybridization station where it is connected to a fluiddelivery system. After hybridization, a rinsing/washing step occurs.Following hybridization and appropriate rinsing/washing, the housedsubstrate may be aligned on a detection or imaging system. Descriptionsof these steps are described in detail in U.S. Pat. No. 5,959,098, whichis hereby incorporated herein by reference in its entirety for allpurposes.

All publications and patent applications cited above are incorporated byreference in their entirety for all purposes to the same extent as ifeach individual publication or patent application were specifically andindividually indicated to be so incorporated by reference. Although thepresent invention has been described in some detail by way ofillustration and example for purposes of clarity and understanding, itwill be apparent that certain changes and modifications may be practicedwithin the scope of the appended claims.

What is claimed is:
 1. A method for improving image flatness of asurface image of a probe array having an array surface roughness, themethod comprising: imaging one or more fiducials of the probe array at aplurality of positions along an axis of translation and determining abest position measurement for each of the fiducials at which the imagingis sharpest; generating a surface fit profile based on a plurality ofthe best position measurements; and imaging the probe array andadjusting one or more surface non-flatness parameters based on thesurface fit profile to improve the image flatness of the surface imageof the probe array.
 2. The method of claim 1, wherein the surface fitprofile is generated using a surface-fitting algorithm.
 3. The method ofclaim 2, wherein the surface-fitting algorithm comprises at least one ofa least square algorithm, a sub-plane surface fit algorithm, and a Bspline surface fit.
 4. The method of 1, wherein determining the bestposition measurement comprises using quadratic interpolation for atleast one of the fiducials.
 5. The method of claim 1, wherein the one ormore surface non-flatness parameters comprise a probe array tilt angle.6. The method of claim 5, wherein adjusting the one or more surfacenon-flatness parameters comprises adjusting a position of a stage onwhich the probe array is mounted.
 7. The method of claim 6, wherein thestage is a two-axis tilt stage.
 8. The method of claim 6, wherein thestage is a three-axis translation stage.
 9. The method of claim 1,wherein the one or more surface non-flatness parameters comprise anoptical parameter.
 10. The method of claim 1, wherein the one or moresurface non-flatness parameters comprise a focal plane position.
 11. Themethod of claim 1, wherein the fiducials comprise at least 4 fiducials.12. The method of claim 11, wherein the fiducials comprise at least 5fiducials.
 13. The method of claim 12, wherein the fiducials comprise atleast 9 fiducials.
 14. The method of claim 13, wherein the fiducialscomprise 12 fiducials.
 15. The method of claim 14, wherein the fiducialscomprise 15 fiducials.
 16. The method of claim 1, wherein the axis oftranslation is perpendicular to a plane of the probe array.
 17. Themethod of claim 1, wherein imaging the one or more fiducials comprisesadjusting a position of a stage on which the probe array is mounted. 18.The method of claim 1, wherein the probe array is a DNA array.
 19. Themethod of claim 1, wherein the probe array is a peptide array.
 20. Themethod of claim 1, wherein the probe array comprises a plurality ofsub-arrays.
 21. The method of claim 20, wherein the one or morefiducials are of a corner sub-array of the probe array.